scholarly journals Evaluation of the ACCESS – chemistry–climate model for the Southern Hemisphere

2016 ◽  
Vol 16 (4) ◽  
pp. 2401-2415 ◽  
Author(s):  
Kane A. Stone ◽  
Olaf Morgenstern ◽  
David J. Karoly ◽  
Andrew R. Klekociuk ◽  
W. John French ◽  
...  
Keyword(s):  
Southern Hemisphere ◽  
Zonal Wind ◽  
Ozone Depletion ◽  
Climate Model ◽  
Similar Amount ◽  
Earth System ◽  
South Pole ◽  
The South ◽  
Total Column Ozone ◽  
Australian Climate

Abstract. Chemistry–climate models are important tools for addressing interactions of composition and climate in the Earth system. In particular, they are used to assess the combined roles of greenhouse gases and ozone in Southern Hemisphere climate and weather. Here we present an evaluation of the Australian Community Climate and Earth System Simulator – chemistry–climate model (ACCESS-CCM), focusing on the Southern Hemisphere and the Australian region. This model is used for the Australian contribution to the international Chemistry–Climate Model Initiative, which is soliciting hindcast, future projection and sensitivity simulations. The model simulates global total column ozone (TCO) distributions accurately, with a slight delay in the onset and recovery of springtime Antarctic ozone depletion, and consistently higher ozone values. However, October-averaged Antarctic TCO from 1960 to 2010 shows a similar amount of depletion compared to observations. Comparison with model precursors shows large improvements in the representation of the Southern Hemisphere stratosphere, especially in TCO concentrations. A significant innovation is seen in the evaluation of simulated vertical profiles of ozone and temperature with ozonesonde data from Australia, New Zealand and Antarctica from 38 to 90° S. Excess ozone concentrations (greater than 26 % at Davis and the South Pole during winter) and stratospheric cold biases (up to 10 K at the South Pole during summer and autumn) outside the period of perturbed springtime ozone depletion are seen during all seasons compared to ozonesondes. A disparity in the vertical location of ozone depletion is seen: centred around 100 hPa in ozonesonde data compared to above 50 hPa in the model. Analysis of vertical chlorine monoxide profiles indicates that colder Antarctic stratospheric temperatures (possibly due to reduced mid-latitude heat flux) are artificially enhancing polar stratospheric cloud formation at high altitudes. The model's inability to explicitly simulate a supercooled ternary solution may also explain the lack of depletion at lower altitudes. Analysis of the simulated Southern Annular Mode (SAM) index compares well with ERA-Interim data, an important metric for correct representation of Australian climate. Accompanying these modulations of the SAM, 50 hPa zonal wind differences between 2001–2010 and 1979–1998 show increasing zonal wind strength southward of 60° S during December for both the model simulations and ERA-Interim data. These model diagnostics show that the model reasonably captures the stratospheric ozone-driven chemistry–climate interactions important for Australian climate and weather while highlighting areas for future model development.

scholarly journals Evaluation of the Australian Community Climate and Earth-System Simulator Chemistry-Climate Model

2015 ◽  
Vol 15 (13) ◽  
pp. 19161-19196
Author(s):  
K. A. Stone ◽  
O. Morgenstern ◽  
D. J. Karoly ◽  
A. R. Klekociuk ◽  
W. J. R. French ◽  
...  
Keyword(s):  
Southern Hemisphere ◽  
Zonal Wind ◽  
Ozone Depletion ◽  
Climate Model ◽  
Stratospheric Ozone ◽  
Similar Amount ◽  
Earth System ◽  
Total Column Ozone ◽  
Australian Community ◽  
Community Climate

Abstract. Chemistry climate models are important tools for addressing interactions of composition and climate in the Earth System. In particular, they are used for assessing the combined roles of greenhouse gases and ozone in Southern Hemisphere climate and weather. Here we present an evaluation of the Australian Community Climate and Earth System Simulator-Chemistry Climate Model, focusing on the Southern Hemisphere and the Australian region. This model is used for the Australian contribution to the international Chemistry-Climate Model Initiative, which is soliciting hindcast, future projection and sensitivity simulations. The model simulates global total column ozone (TCO) distributions accurately, with a slight delay in the onset and recovery of springtime Antarctic ozone depletion, and consistently higher ozone values. However, October averaged Antarctic TCO from 1960 to 2010 show a similar amount of depletion compared to observations. A significant innovation is the evaluation of simulated vertical profiles of ozone and temperature with ozonesonde data from Australia, New Zealand and Antarctica from 38 to 90° S. Excess ozone concentrations (up to 26.4 % at Davis during winter) and stratospheric cold biases (up to 10.1 K at the South Pole) outside the period of perturbed springtime ozone depletion are seen during all seasons compared to ozonesondes. A disparity in the vertical location of ozone depletion is seen: centered around 100 hPa in ozonesonde data compared to above 50 hPa in the model. Analysis of vertical chlorine monoxide profiles indicates that colder Antarctic stratospheric temperatures (possibly due to reduced mid-latitude heat flux) are artificially enhancing polar stratospheric cloud formation at high altitudes. The models inability to explicitly simulated supercooled ternary solution may also explain the lack of depletion at lower altitudes. The simulated Southern Annular Mode (SAM) index compares well with ERA-Interim data. Accompanying these modulations of the SAM, 50 hPa zonal wind differences between 2001–2010 and 1979–1998 show increasing zonal wind strength southward of 60° S during December for both the model simulations and ERA-Interim data. These model diagnostics shows that the model reasonably captures the stratospheric ozone driven chemistry-climate interactions important for Australian climate and weather while highlighting areas for future model development.

Southern Hemisphere Stationary Wave Response to Changes of Ozone and Greenhouse Gases

2013 ◽  
Vol 26 (24) ◽  
pp. 10205-10217 ◽  
Author(s):  
Lei Wang ◽  
Paul J. Kushner ◽  
Darryn W. Waugh
Keyword(s):  
Phase Shift ◽  
Greenhouse Gases ◽  
Southern Hemisphere ◽  
Ozone Depletion ◽  
Wave Amplitude ◽  
Climate Model ◽  
Recovery Period ◽  
Stationary Wave ◽  
Early Summer ◽  
Model Simulations

Abstract The Southern Hemisphere (SH) stratospheric stationary wave amplitude increased significantly in late spring and early summer during the last two decades of the twentieth century. A suite of chemistry climate model simulations are examined to explore the underlying cause and the separate effects of anthropogenic forcing from ozone depleting substances (ODSs) and greenhouse gases (GHGs) in the past and projected SH stationary wave evolution. The model simulations produce trends in the wave amplitude similar to that observed, although somewhat weaker. In simulations with changing ODSs, this increase in amplitude is reproduced during the ozone depletion period and is reversed during the ozone recovery period. This response is related to changes in the strength and timing of the breakdown of the SH polar vortex associated with ozone depletion and recovery. GHG increases have little impact on the simulated stratospheric stationary wave amplitude but are projected to induce an eastward phase shift of the waves. This phase shift is linked to the strengthening of the subtropical jets driven by GHG forcing via sea surface warming.

scholarly journals Antarctic ozone depletion between 1960 and 1980 in observations and chemistry–climate model simulations

2016 ◽  
Vol 16 (24) ◽  
pp. 15619-15627 ◽  
Author(s):  
Ulrike Langematz ◽  
Franziska Schmidt ◽  
Markus Kunze ◽  
Gregory E. Bodeker ◽  
Peter Braesicke
Keyword(s):  
Ozone Depletion ◽  
Climate Model ◽  
Total Column Ozone ◽  
Antarctic Ozone ◽  
Climate Model Simulations ◽  
Ozone Depleting Substances ◽  
Column Ozone ◽  
The Antarctic ◽  
Total Column

Abstract. The year 1980 has often been used as a benchmark for the return of Antarctic ozone to conditions assumed to be unaffected by emissions of ozone-depleting substances (ODSs), implying that anthropogenic ozone depletion in Antarctica started around 1980. Here, the extent of anthropogenically driven Antarctic ozone depletion prior to 1980 is examined using output from transient chemistry–climate model (CCM) simulations from 1960 to 2000 with prescribed changes of ozone-depleting substance concentrations in conjunction with observations. A regression model is used to attribute CCM modelled and observed changes in Antarctic total column ozone to halogen-driven chemistry prior to 1980. Wintertime Antarctic ozone is strongly affected by dynamical processes that vary in amplitude from year to year and from model to model. However, when the dynamical and chemical impacts on ozone are separated, all models consistently show a long-term, halogen-induced negative trend in Antarctic ozone from 1960 to 1980. The anthropogenically driven ozone loss from 1960 to 1980 ranges between 26.4 ± 3.4 and 49.8 ± 6.2 % of the total anthropogenic ozone depletion from 1960 to 2000. An even stronger ozone decline of 56.4 ± 6.8 % was estimated from ozone observations. This analysis of the observations and simulations from 17 CCMs clarifies that while the return of Antarctic ozone to 1980 values remains a valid milestone, achieving that milestone is not indicative of full recovery of the Antarctic ozone layer from the effects of ODSs.

scholarly journals Sensitivity of the southern hemisphere tropospheric jet response to Antarctic ozone depletion: prescribed versus interactive chemistry

2020 ◽  
Author(s):  
Sabine Haase ◽  
Jaika Fricke ◽  
Tim Kruschke ◽  
Sebastian Wahl ◽  
Katja Matthes
Keyword(s):  
Southern Hemisphere ◽  
Ozone Depletion ◽  
Climate Models ◽  
Climate Model ◽  
Stratospheric Ozone ◽  
Austral Summer ◽  
Jet Stream ◽  
Heating Rates ◽  
Sea Ice Extent ◽  
Poleward Shift

Abstract. Southern hemisphere lower stratospheric ozone depletion has been shown to lead to a poleward shift of the tropospheric jet stream during austral summer, influencing surface atmosphere and ocean conditions, such as surface temperatures and sea ice extent. The characteristics of stratospheric and tropospheric responses to ozone depletion, however, differ largely among climate models depending on the representation of ozone in the models. The most accurate way to represent ozone in a model is to calculate it interactively. However, due to computational costs, in particular for long-term coupled ocean-atmosphere model integrations, the more common way is to prescribe ozone from observations or calculated model fields. Here, we investigate the difference between an interactive and a specified chemistry version of the same atmospheric model in a fully-coupled setup using a 9-member chemistry-climate model ensemble. In the specified chemistry version of the model the ozone fields are prescribed using the output from the interactive chemistry model version. In contrast to earlier studies, we use daily-resolved ozone fields in the specified chemistry simulations to achieve a better comparability between the ozone forcing with and without interactive chemistry. We find that although the short-wave heating rate trend in response to ozone depletion is the same in the different chemistry settings, the interactive chemistry ensemble shows a stronger trend in polar cap stratospheric temperatures (by about 0.7 K per decade) and circumpolar stratospheric zonal mean zonal winds (by about 1.6 m/s per decade) as compared to the specified chemistry ensemble. This difference between interactive and specified chemistry in the stratospheric response to ozone depletion also affects the tropospheric response, namely the poleward shift of the tropospheric jet stream. We attribute part of these differences to the missing representation of feedbacks between chemistry and dynamics in the specified chemistry ensemble, which affect the dynamical heating rates, and part of it to the lack of spatial asymmetries in the prescribed ozone fields. This effect is investigated using a sensitivity ensemble that was forced by a three-dimensional instead of a two–dimensional ozone field. This study emphasizes the value of interactive chemistry for the representation of the southern hemisphere tropospheric jet response to ozone depletion and infers that for periods with strong ozone variability (trends) the details of the ozone forcing can be crucial for representing southern hemispheric climate variability.

Replacing Chlorofluorocarbons in Industry

1990 ◽  
Vol 33 (6) ◽  
pp. 23-26
Author(s):  
Kurt Weigel
Keyword(s):  
Decision Making ◽  
Ozone Depletion ◽  
Scientific Evidence ◽  
Decision Making Process ◽  
South Pole ◽  
The South ◽  
Blowing Agents ◽  
Research Organizations ◽  
Speed Up ◽  
The Impact

Scientific evidence indicates that ozone depletion over the South Pole is more serious than was suspected a few years ago. As a result, production of the principal ozone-depleting compounds is scheduled to be phased out over the next decade. The impact of the elimination of these chemicals on industries will be immediate and significant, with the aerospace and electronics industries among the most severely affected. Alternative solvents, refrigerants, and foam-blowing agents are being developed, but will not be available in commercial quantities until 1992 at the earliest. Meanwhile, CFC users are working with the chemical manufacturers, EPA, DoD, and various research organizations, to speed up the process of identifying and implementing alternative compounds or processes. Most of the proposed alternatives have some drawbacks when compared with CFCs, but can be implemented safely if the user takes the time to understand the issues thoroughly and involves all affected parties in the decision-making process.

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 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 Analisis Pola Distribusi Unsur-Unsur Cuaca di Lapisan Atas Atmosfer pada Bulan Januari dan Agustus di Manado

Jurnal MIPA ◽  
2014 ◽  
Vol 3 (1) ◽  
pp. 20
Author(s):  
Carisz Kainama ◽  
Seni H. J. Tongkukut ◽  
Wandayantolis .
Keyword(s):  
Temperature Distribution ◽  
Wind Speed ◽  
Distribution Pattern ◽  
Southern Hemisphere ◽  
Zonal Wind ◽  
Meridional Wind ◽  
The South ◽  
The West ◽  
The North ◽  
North Sulawesi

Telah dibuat peta pola distribusi suhu udara, kelembapan udara, dan kecepatan angin di lapisan atas pada bulan Januari dan Agustus di Manado, dengan menggunakan software Surfer 10. Hasil analisis menunjukkan bahwa di bulan Januari pada lapisan 850 mb suhu di belahan bumi selatan (BBS) lebih tinggi dari belahan bumi utara (BBU), kelembapan lebih besar ke arah Sulawesi Utara, angin zonal baratan di BBS dan angin zonal timuran di BBU, sedangkan angin meridional dominan dari arah utara. Pada lapisan 500 mb dan 300 mb penyebaran suhu hampir merata untuk setiap wilayah dengan suhu terendah terdapat di sekitar wilayah Sulawesi Utara, kelembapan lebih besar ke arah BBS, angin zonal dari arah timur, sedangkan angin meridional dari arah utara di BBU dan dari arah selatan di BBS. Perbedaan kecepatan angin antar lapisan tidak signifikan. Di bulan Agustus, pada lapisan 850 mb suhu di BBU lebih tinggi dari BBS, kelembapan lebih besar ke arah Maluku, angin zonal dari arah timur di BBU dan dari arah barat di BBS, sedangkan angin meridional dominan dari arah selatan. Pada lapisan 500 mb penyebaran suhu hampir merata dengan suhu tertingi terdapat di wilayah Davao, dan pada lapisan 300 mb penyebaran suhu sama dengan bulan Januari. Pada lapisan 500 mb dan 300 mb kelembapan lebih besar ke arah timur, sedangkan angin zonal dari arah timur. Angin meridional dominan dari arah selatan pada lapisan 500 mb dan dominan dari arah utara pada lapisan 300 mb.A map of distribution pattern of temperature, humidity, and wind speed and direction in the upper layer of Manado in January and August had been created using software Surfer 10. The analysis showed that, in January at 850 mb layer, the temperature in southern hemisphere (SH) is higher than that in northern hemisphere (NH), the humidity is higher to the North Sulawesi, westerly zonal wind is in SH and easterly zonal wind is in NH, and meridional wind is dominant from the north. At 500 mb and 300 mb layer, temperature distribution is almost evenly for each region with the lowest temperature is around the North Sulawesi area, the humidity is higher to the SH, the zonal wind is from the east, and the meridional wind is from the north at NH and from the south in SH. Wind speed difference between the layers is not significant. In August at 850 mb layer, the temperature in NH is higher than that in SH, the humidity is greater to Moluccas, the zonal wind is from the east at NH and from the west in the SH, and the meridional wind is dominant from the south. At 500 mb layer, temperature distribution is almost evenly with the highest one is in the Davao region, and at 300 mb layer, temperature is similar to that in January. At 500 mb and 300 mb layer, the humidity is greater eastward.

scholarly journals Hemispheric ozone variability indices derived from satellite observations and comparison to a coupled chemistry-climate model

2006 ◽  
Vol 6 (12) ◽  
pp. 5105-5120 ◽  
Author(s):  
T. Erbertseder ◽  
V. Eyring ◽  
M. Bittner ◽  
M. Dameris ◽  
V. Grewe
Keyword(s):  
Southern Hemisphere ◽  
Northern Hemisphere ◽  
Total Ozone ◽  
Planetary Wave ◽  
Climate Model ◽  
Model Simulation ◽  
Wave Activity ◽  
Satellite Observations ◽  
Ozone Hole ◽  
Total Column Ozone

Abstract. Total column ozone is used to trace the dynamics of the lower and middle stratosphere which is governed by planetary waves. In order to analyse the planetary wave activity a Harmonic Analysis is applied to global multi-year total ozone observations from the Total Ozone Monitoring Spectrometer (TOMS). As diagnostic variables we introduce the hemispheric ozone variability indices one and two. They are defined as the hemispheric means of the amplitudes of the zonal waves number one and two, respectively, as traced by the total ozone field. The application of these indices as a simple diagnostic for the evaluation of coupled chemistry-climate models (CCMs) is demonstrated by comparing results of the CCM ECHAM4.L39(DLR)/CHEM (hereafter: E39/C) against satellite observations. It is quantified to what extent a multi-year model simulation of E39/C (representing "2000" climate conditions) is able to reproduce the zonal and hemispheric planetary wave activity derived from TOMS data (1996–2004, Version 8). Compared to the reference observations the hemispheric ozone variability indices one and two of E39/C are too high in the Northern Hemisphere and too low in the Southern Hemisphere. In the Northern Hemisphere, where the agreement is generally better, E39/C produces too strong a planetary wave one activity in winter and spring and too high an interannual variability. For the Southern Hemisphere we reveal that the indices from observations and model differ significantly during the ozone hole season. The indices are used to give reasons for the late formation of the Antarctic ozone hole, the insufficient vortex elongation and eventually the delayed final warming in E39/C. In general, the hemispheric ozone variability indices can be regarded as a simple and robust diagnostic to quantify model-observation differences concerning planetary wave activity. It allows a first-guess on how the dynamics is represented in a model simulation before applying costly and more specific diagnostics.

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