scholarly journals Review of ‘PSCs initiated by mountain waves in a global chemistry-climate model: A missing piece in fully modelling polar stratospheric ozone depletion’, by A. Orr et al.

2020 ◽  
Keyword(s):  
Ozone Depletion ◽  
Climate Model ◽  
Stratospheric Ozone ◽  
Stratospheric Ozone Depletion ◽  
Mountain Waves

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 Interactive ozone and methane chemistry in GISS-E2 historical and future climate simulations

2013 ◽  
Vol 13 (5) ◽  
pp. 2653-2689 ◽  
Author(s):  
D. T. Shindell ◽  
O. Pechony ◽  
A. Voulgarakis ◽  
G. Faluvegi ◽  
L. Nazarenko ◽  
...  
Keyword(s):  
Ocean Circulation ◽  
Ozone Depletion ◽  
Tropospheric Ozone ◽  
Radiative Forcing ◽  
Climate Model ◽  
Stratospheric Ozone ◽  
Boreal Summer ◽  
Tropospheric Temperature ◽  
Stratospheric Ozone Depletion ◽  
Model Calculations

Abstract. The new generation GISS climate model includes fully interactive chemistry related to ozone in historical and future simulations, and interactive methane in future simulations. Evaluation of ozone, its tropospheric precursors, and methane shows that the model captures much of the large-scale spatial structure seen in recent observations. While the model is much improved compared with the previous chemistry-climate model, especially for ozone seasonality in the stratosphere, there is still slightly too rapid stratospheric circulation, too little stratosphere-to-troposphere ozone flux in the Southern Hemisphere and an Antarctic ozone hole that is too large and persists too long. Quantitative metrics of spatial and temporal correlations with satellite datasets as well as spatial autocorrelation to examine transport and mixing are presented to document improvements in model skill and provide a benchmark for future evaluations. The difference in radiative forcing (RF) calculated using modeled tropospheric ozone versus tropospheric ozone observed by TES is only 0.016 W m−2. Historical 20th Century simulations show a steady increase in whole atmosphere ozone RF through 1970 after which there is a decrease through 2000 due to stratospheric ozone depletion. Ozone forcing increases throughout the 21st century under RCP8.5 owing to a projected recovery of stratospheric ozone depletion and increases in methane, but decreases under RCP4.5 and 2.6 due to reductions in emissions of other ozone precursors. RF from methane is 0.05 to 0.18 W m−2 higher in our model calculations than in the RCP RF estimates. The surface temperature response to ozone through 1970 follows the increase in forcing due to tropospheric ozone. After that time, surface temperatures decrease as ozone RF declines due to stratospheric depletion. The stratospheric ozone depletion also induces substantial changes in surface winds and the Southern Ocean circulation, which may play a role in a slightly stronger response per unit forcing during later decades. Tropical precipitation shifts south during boreal summer from 1850 to 1970, but then shifts northward from 1970 to 2000, following upper tropospheric temperature gradients more strongly than those at the surface.

scholarly journals Interactive ozone and methane chemistry in GISS-E2 historical and future climate simulations

2012 ◽  
Vol 12 (9) ◽  
pp. 23513-23602 ◽  
Author(s):  
D. T. Shindell ◽  
O. Pechony ◽  
A. Voulgarakis ◽  
G. Faluvegi ◽  
L. Nazarenko ◽  
...  
Keyword(s):  
Ocean Circulation ◽  
Ozone Depletion ◽  
Tropospheric Ozone ◽  
Radiative Forcing ◽  
Climate Model ◽  
Stratospheric Ozone ◽  
Boreal Summer ◽  
Tropospheric Temperature ◽  
Stratospheric Ozone Depletion ◽  
Model Calculations

Abstract. The new generation GISS climate model includes fully interactive chemistry related to ozone in historical and future simulations, and interactive methane in future simulations. Evaluation of ozone, its tropospheric precursors, and methane shows that the model captures much of the large-scale spatial structure seen in recent observations. While the model is much improved compared with the previous chemistry-climate model, especially for ozone seasonality in the stratosphere, there is still slightly too rapid stratospheric circulation too little stratosphere-to-troposphere ozone flux in the Southern Hemisphere and an Antarctic ozone hole that is too large and persists too long quantitative metrics of spatial and temporal correlations with satellite datasets as well as spatial autocorrelation to examine transport and mixing are presented to document improvements in model skill and provide a benchmark for future evaluations. The difference in radiative forcing (RF) calculated using modeled tropospheric ozone versus tropospheric ozone observed by TES is only 0.016 W m−2. Historical 20th Century simulations show a steady increase in whole atmosphere ozone RF through 1970 after which there is a decrease through 2000 due to stratospheric ozone depletion. Ozone forcing increases in the future under RCP8.5 owing to a projected recovery of stratospheric ozone depletion and increases in methane, but decreases under other RCPs due to reductions in emissions of other ozone precursors. RF from methane is 0.05 to 0.18 W m−2 higher in our model calculations than in the RCP RF estimates. The surface temperature response to ozone through 1970 follows the increase in forcing due to tropospheric ozone. After that time, surface temperatures decrease as ozone RF declines due to stratospheric depletion. The stratospheric ozone depletion also induces substantial changes in surface winds and the Southern Ocean circulation, which may play a role in a slightly stronger response per unit forcing during later decades. Tropical precipitation shifts south during boreal summer from 1850 to 1970, but then shifts northward from 1970 to 2000, following upper tropospheric temperature gradients more strongly than those at the surface.

Impacts of Stratospheric Ozone Extremes on Arctic High Cloud

2021 ◽  
Author(s):  
Karen Smith ◽  
Sarah Maleska ◽  
John Virgin
Keyword(s):  
Northern Hemisphere ◽  
Ozone Depletion ◽  
Climate Model ◽  
Stratospheric Ozone ◽  
Global Climate Models ◽  
Arctic Climate ◽  
The Arctic ◽  
Stratospheric Ozone Depletion ◽  
High Cloud ◽  
The Impact

<p>Stratospheric ozone depletion in the Antarctic is well known to cause changes in Southern Hemisphere tropospheric climate; however, because of its smaller magnitude in the Arctic, the effects of stratospheric ozone depletion on Northern Hemisphere tropospheric climate are not as obvious or well understood. Recent research using both global climate models and observational data has determined that the impact of ozone depletion on ozone extremes can affect interannual variability in tropospheric circulation in the Northern Hemisphere in spring. To further this work, we use a coupled chemistry–climate model to examine the difference in high cloud between years with anomalously low and high Arctic stratospheric ozone concentrations. We find that low ozone extremes during the late twentieth century, when ozone-depleting substances (ODS) emissions are higher, are related to a decrease in upper tropospheric stability and an increase in high cloud fraction, which may contribute to enhanced Arctic surface warming in spring through a positive longwave cloud radiative effect. A better understanding of how Arctic climate is affected by ODS emissions, ozone depletion, and ozone extremes will lead to improved predictions of Arctic climate and its associated feedbacks with atmospheric fields as ozone levels recover.</p>

Impacts of Stratospheric Ozone Extremes on Arctic High Cloud

2020 ◽  
Vol 33 (20) ◽  
pp. 8869-8884
Author(s):  
Sarah Maleska ◽  
Karen L. Smith ◽  
John Virgin
Keyword(s):  
Northern Hemisphere ◽  
Ozone Depletion ◽  
Climate Model ◽  
Stratospheric Ozone ◽  
Global Climate Models ◽  
Arctic Climate ◽  
The Arctic ◽  
Stratospheric Ozone Depletion ◽  
High Cloud ◽  
The Impact

AbstractStratospheric ozone depletion in the Antarctic is well known to cause changes in Southern Hemisphere tropospheric climate; however, because of its smaller magnitude in the Arctic, the effects of stratospheric ozone depletion on Northern Hemisphere tropospheric climate are not as obvious or well understood. Recent research using both global climate models and observational data has determined that the impact of ozone depletion on ozone extremes can affect interannual variability in tropospheric circulation in the Northern Hemisphere in spring. To further this work, we use a coupled chemistry–climate model to examine the difference in high cloud between years with anomalously low and high Arctic stratospheric ozone concentrations. We find that low ozone extremes during the late twentieth century, when ozone-depleting substances (ODS) emissions are higher, are related to a decrease in upper tropospheric stability and an increase in high cloud fraction, which may contribute to enhanced Arctic surface warming in spring through a positive longwave cloud radiative effect. A better understanding of how Arctic climate is affected by ODS emissions, ozone depletion, and ozone extremes will lead to improved predictions of Arctic climate and its associated feedbacks with atmospheric fields as ozone levels recover.

scholarly journals The Transient Response of the Southern Ocean to Stratospheric Ozone Depletion

2016 ◽  
Vol 29 (20) ◽  
pp. 7383-7396 ◽  
Author(s):  
William J. M. Seviour ◽  
Anand Gnanadesikan ◽  
Darryn W. Waugh
Keyword(s):  
Southern Ocean ◽  
Transient Response ◽  
Ozone Depletion ◽  
Climate Models ◽  
Climate Model ◽  
Stratospheric Ozone ◽  
Natural Variability ◽  
Stratospheric Ozone Depletion ◽  
Initial State ◽  
Cooling Period

Abstract Recent studies have suggested that the response of the Southern Ocean to stratospheric ozone depletion is nonmonotonic in time; consisting of an initial cooling followed by a long-term warming. This result may be significant for the attribution of observed Southern Ocean temperature and sea ice trends, but the time scale and magnitude of the response is poorly constrained, with a wide spread among climate models. Furthermore, a long-lived initial cooling period has only been observed in a model with idealized geometry and lacking an explicit representation of ozone. Here the authors calculate the transient response of the Southern Ocean to a step-change in ozone in a comprehensive coupled climate model, GFDL-ESM2Mc. The Southern Ocean responds to ozone depletion with an initial cooling, lasting 25 yr, followed by a warming. The authors extend previous studies to investigate the dependence of the response on the ozone forcing as well as the regional pattern of this response. The response of the Southern Ocean relative to natural variability is shown to be largely independent of the initial state. However, the magnitude of this response is much less than that of natural variability found in the model, which limits its influence and detectability.

Impacts of stratospheric ozone extremes on Arctic high cloud

2020 ◽  
Author(s):  
Karen Smith ◽  
Sarah Maleska ◽  
John Virgin
Keyword(s):  
Northern Hemisphere ◽  
Ozone Depletion ◽  
Climate Model ◽  
Stratospheric Ozone ◽  
Global Climate Models ◽  
Arctic Climate ◽  
The Arctic ◽  
Stratospheric Ozone Depletion ◽  
High Cloud ◽  
The Impact

<p>Stratospheric ozone depletion in the Antarctic is well known to cause changes in Southern Hemisphere tropospheric climate; however, due to its smaller magnitude in the Arctic, the effects of stratospheric ozone depletion on Northern Hemisphere tropospheric climate are not as obvious or well understood. Recent research using both global climate models and observational data has determined that the impact of ozone depletion on ozone extremes can affect interannual variability in tropospheric circulation in the Northern Hemisphere in spring. To further this work, we use a coupled chemistry-climate model to examine the difference in high cloud between years with anomalously low and high Arctic stratospheric ozone concentrations. We find that low ozone extremes during the late twentieth century, when ODS emissions are higher, are related to a decrease in upper tropospheric stability and an increase in high cloud fraction, which may have contributed to Arctic surface warming via a positive longwave cloud radiative effect in the past few decades compared to other regions. A better understanding of how Arctic climate is affected by ODS emissions, ozone depletion and ozone extremes will lead to improved predictions of Arctic climate and its associated feedbacks with atmospheric fields as ozone levels recover.</p>

scholarly journals PSCs initiated by mountain waves in a global chemistry-climate model: A missing piece in fully modelling polar stratospheric ozone depletion

2020 ◽  
Author(s):  
Andrew Orr ◽  
J. Scott Hosking ◽  
Aymeric Delon ◽  
Lars Hoffmann ◽  
Reinhold Spang ◽  
...  
Keyword(s):  
Antarctic Peninsula ◽  
Ozone Depletion ◽  
Stratospheric Ozone ◽  
Temperature Fluctuations ◽  
Stratospheric Ozone Depletion ◽  
Synoptic Scale ◽  
Mountain Waves ◽  
Cooling Phase ◽  
Ice Water ◽  
The Antarctic

Abstract. An important source of polar stratospheric clouds (PSCs), which play a crucial role in controlling polar stratospheric ozone depletion, is from the temperature fluctuations induced by mountain waves. These enable stratospheric temperatures to fall below the threshold value for PSC formation in regions of negative temperature perturbations or cooling-phases induced by the waves even if the synoptic-scale temperatures are too high. However, this formation mechanism is usually missing in global chemistry–climate models because these temperature fluctuations are neither resolved nor parameterised. Here, we investigate in detail the episodic and localised wintertime stratospheric cooling events produced over the Antarctic Peninsula by a parameterisation of mountain-wave-induced temperature fluctuations inserted into a 30-year run of the global chemistry-climate configuration of the UM-UKCA (Unified Model – United Kingdom Chemistry and Aerosol) model. Comparison of the probability distribution of the parameterised cooling-phases with those derived from climatologies of satellite-derived AIRS brightness temperature measurements and high-resolution radiosonde temperature soundings from Rothera Research Station on the Antarctic Peninsula shows that they broadly agree with the AIRS-observations and agree well with the radiosonde-observations, particularly in both cases for the “cold tails” of the distributions. It is further shown that adding the parameterised cooling-phase to the resolved/synoptic-scale temperatures in the UM-UKCA model results in a considerable increase in the number of instances when minimum temperatures fall below the formation temperature for PSCs made from ice water during late austral autumn/early austral winter and early austral spring, and without the additional cooling-phase the ice frost point is rarely exceeded above the Antarctic Peninsula in the model. Similarly, it was found that the formation potential for PSCs made from ice water was many times larger if the additional cooling is included. For PSCs made from NAT particles it was only during October that the additional cooling is required for the NAT temperature threshold to be exceeded (despite more NAT PSCs occurring during other months). The additional cooling-phases also resulted in an increase in the surface area density of NAT particles throughout the winter and early spring, which is important for chlorine activation. The parameterisation scheme was finally shown to make substantial differences to the distribution of total column ozone during October, resulting from a shift in the position of the polar vortex.

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