scholarly journals How Does Downward Planetary Wave Coupling Affect Polar Stratospheric Ozone in the Arctic Winter Stratosphere?

2016 ◽  
Author(s):  
Sandro W. Lubis ◽  
Vered Silverman ◽  
Katja Matthes ◽  
Nili Harnik ◽  
Nour-Eddine Omrani ◽  
...  

Abstract. It is well established that variable wintertime planetary wave forcing in the stratosphere controls the variability of Arctic stratospheric ozone through changes in the strength of the polar vortex and the residual circulation. While previous studies focused on the variations in upward wave flux entering the lower stratosphere, here the impact of downward planetary wave coupling (DWC) on ozone is investigated for the first time. Utilizing the MERRA-2 reanalysis and a fully coupled chemistry-climate simulation with NCAR's Community Earth System Model (CESM1[WACCM]), we find two DWC effects on ozone: (1) the direct effect in which the residual circulation is modified and prevents the typical increase of ozone due to upward planetary wave events in winter, and (2) the indirect effect in which the modification of polar temperature during winter affects the amount of ozone destruction in spring. Winter seasons dominated by DWC events (i.e., reflective winters) are characterized by lower Arctic ozone concentration, while seasons dominated by increased upward wave events (i.e., absorptive winters) are characterized by relatively higher ozone concentration. This behavior is consistent with the cumulative effects of downward and upward planetary wave events on polar stratospheric ozone via the residual circulation and the polar temperature in winter. The results establish a new perspective on dynamical processes controlling stratospheric ozone variability in the Arctic.

2017 ◽  
Vol 17 (3) ◽  
pp. 2437-2458 ◽  
Author(s):  
Sandro W. Lubis ◽  
Vered Silverman ◽  
Katja Matthes ◽  
Nili Harnik ◽  
Nour-Eddine Omrani ◽  
...  

Abstract. It is well established that variable wintertime planetary wave forcing in the stratosphere controls the variability of Arctic stratospheric ozone through changes in the strength of the polar vortex and the residual circulation. While previous studies focused on the variations in upward wave flux entering the lower stratosphere, here the impact of downward planetary wave reflection on ozone is investigated for the first time. Utilizing the MERRA2 reanalysis and a fully coupled chemistry–climate simulation with the Community Earth System Model (CESM1(WACCM)) of the National Center for Atmospheric Research (NCAR), we find two downward wave reflection effects on ozone: (1) the direct effect in which the residual circulation is weakened during winter, reducing the typical increase of ozone due to upward planetary wave events and (2) the indirect effect in which the modification of polar temperature during winter affects the amount of ozone destruction in spring. Winter seasons dominated by downward wave reflection events (i.e., reflective winters) are characterized by lower Arctic ozone concentration, while seasons dominated by increased upward wave events (i.e., absorptive winters) are characterized by relatively higher ozone concentration. This behavior is consistent with the cumulative effects of downward and upward planetary wave events on polar stratospheric ozone via the residual circulation and the polar temperature in winter. The results establish a new perspective on dynamical processes controlling stratospheric ozone variability in the Arctic by highlighting the key role of wave reflection.


2013 ◽  
Vol 70 (12) ◽  
pp. 3977-3994 ◽  
Author(s):  
John R. Albers ◽  
Terrence R. Nathan

Abstract A mechanistic chemistry–dynamical model is used to evaluate the relative importance of radiative, photochemical, and dynamical feedbacks in communicating changes in lower-stratospheric ozone to the circulation of the stratosphere and lower mesosphere. Consistent with observations and past modeling studies of Northern Hemisphere late winter and early spring, high-latitude radiative cooling due to lower-stratospheric ozone depletion causes an increase in the modeled meridional temperature gradient, an increase in the strength of the polar vortex, and a decrease in vertical wave propagation in the lower stratosphere. Moreover, it is shown that, as planetary waves pass through the ozone loss region, dynamical feedbacks precondition the wave, causing a large increase in wave amplitude. The wave amplification causes an increase in planetary wave drag, an increase in residual circulation downwelling, and a weaker polar vortex in the upper stratosphere and lower mesosphere. The dynamical feedbacks responsible for the wave amplification are diagnosed using an ozone-modified refractive index; the results explain recent chemistry–coupled climate model simulations that suggest a link between ozone depletion and increased polar downwelling. The effects of future ozone recovery are also examined and the results provide guidance for researchers attempting to diagnose and predict how stratospheric climate will respond specifically to ozone loss and recovery versus other climate forcings including increasing greenhouse gas abundances and changing sea surface temperatures.


2015 ◽  
Vol 15 (17) ◽  
pp. 9945-9963 ◽  
Author(s):  
N. J. Livesey ◽  
M. L. Santee ◽  
G. L. Manney

Abstract. The well-established "Match" approach to quantifying chemical destruction of ozone in the polar lower stratosphere is applied to ozone observations from the Microwave Limb Sounder (MLS) on NASA's Aura spacecraft. Quantification of ozone loss requires distinguishing transport- and chemically induced changes in ozone abundance. This is accomplished in the Match approach by examining cases where trajectories indicate that the same air mass has been observed on multiple occasions. The method was pioneered using ozonesonde observations, for which hundreds of matched ozone observations per winter are typically available. The dense coverage of the MLS measurements, particularly at polar latitudes, allows matches to be made to thousands of observations each day. This study is enabled by recently developed MLS Lagrangian trajectory diagnostic (LTD) support products. Sensitivity studies indicate that the largest influence on the ozone loss estimates are the value of potential vorticity (PV) used to define the edge of the polar vortex (within which matched observations must lie) and the degree to which the PV of an air mass is allowed to vary between matched observations. Applying Match calculations to MLS observations of nitrous oxide, a long-lived tracer whose expected rate of change is negligible on the weekly to monthly timescales considered here, enables quantification of the impact of transport errors on the Match-based ozone loss estimates. Our loss estimates are generally in agreement with previous estimates for selected Arctic winters, though indicating smaller losses than many other studies. Arctic ozone losses are greatest during the 2010/11 winter, as seen in prior studies, with 2.0 ppmv (parts per million by volume) loss estimated at 450 K potential temperature (~ 18 km altitude). As expected, Antarctic winter ozone losses are consistently greater than those for the Arctic, with less interannual variability (e.g., ranging between 2.3 and 3.0 ppmv at 450 K). This study exemplifies the insights into atmospheric processes that can be obtained by applying the Match methodology to a densely sampled observation record such as that from Aura MLS.


2021 ◽  
Author(s):  
Marina Friedel ◽  
Gabriel Chiodo ◽  
Andrea Stenke ◽  
Daniela Domeisen ◽  
Stephan Fueglistaler ◽  
...  

Abstract Massive spring ozone loss due to anthropogenic emissions of ozone depleting substances is not limited to the austral hemisphere, but can also occur in the Arctic. Previous studies have suggested a link between springtime Arctic ozone depletion and Northern Hemispheric surface climate, which might add surface predictability. However, so far it has not been possible to isolate the role of stratospheric ozone from dynamical downward impacts. For the first time, we quantify the impact of springtime Arctic ozone depletion on surface climate using observations and targeted chemistry-climate model experiments to isolate the effects of ozone feedbacks. We find that springtime stratospheric ozone depletion is followed by surface anomalies in precipitation and temperature resembling a positive Arctic Oscillation. Most notably, we show that these anomalies, affecting large portions of the Northern Hemisphere, cannot be explained by dynamical variability alone, but are to a significant degree driven by stratospheric ozone. The surface signal is linked to reduced shortwave absorption by stratospheric ozone, forcing persistent negative temperature anomalies in the lower stratosphere and a delayed breakup of the polar vortex - analogous to ozone-surface coupling in the Southern Hemisphere.These results suggest that Arctic stratospheric ozone actively forces springtime Northern Hemispheric surface climate and thus provides a source of predictability on seasonal scales.


2015 ◽  
Vol 15 (7) ◽  
pp. 10041-10083 ◽  
Author(s):  
N. J. Livesey ◽  
M. L. Santee ◽  
G. L. Manney

Abstract. The well-established "Match" approach to quantifying chemical destruction of ozone in the polar lower stratosphere is applied to ozone observations from the Microwave Limb Sounder (MLS) on NASA's Aura spacecraft. Quantification of ozone loss requires distinguishing transport- and chemically induced changes in ozone abundance. This is accomplished in the Match approach by examining cases where trajectories indicate that the same airmass has been observed on multiple occasions. The method was pioneered using ozone sonde observations, for which hundreds of matched ozone observations per winter are typically available. The dense coverage of the MLS measurements, particularly at polar latitudes, allows matches to be made to thousands of observations each day. This study is enabled by recently developed MLS Lagrangian Trajectory Diagnostic (LTD) support products. Sensitivity studies indicate that the largest influence on the ozone loss estimates are the value of potential vorticity (PV) used to define the edge of the polar vortex (within which matched observations must lie) and the degree to which the PV of an airmass is allowed to vary between matched observations. Applying Match calculations to MLS observations of nitrous oxide, a long-lived tracer whose expected rate of change on these timescales is negligible, enables quantification of the impact of transport errors on the Match-based ozone loss estimates. Our loss estimates are generally in agreement with previous estimates for selected Arctic winters, though indicating smaller losses than many other studies. Arctic ozone losses are greatest during the 2010/11 winter, as seen in prior studies, with 2.0 ppmv (parts per million by volume) loss estimated at 450 K potential temperature. As expected, Antarctic winter ozone losses are consistently greater than those for the Arctic, with less interannual variability (e.g., ranging between 2.3 and 3.0 ppmv at 450 K). This study exemplifies the insights into atmospheric processes that can be obtained by applying the Match methodology to a densely sampled observation record such as that from Aura MLS.


2011 ◽  
Vol 24 (16) ◽  
pp. 4210-4229 ◽  
Author(s):  
Tiffany A. Shaw ◽  
Judith Perlwitz ◽  
Nili Harnik ◽  
Paul A. Newman ◽  
Steven Pawson

Abstract The impact of stratospheric ozone changes on downward wave coupling between the stratosphere and troposphere in the Southern Hemisphere is investigated using a suite of Goddard Earth Observing System chemistry–climate model (GEOS CCM) simulations. Downward wave coupling occurs when planetary waves reflected in the stratosphere impact the troposphere. In reanalysis data, the climatological coupling occurs from September to December when the stratospheric basic state has a well-defined high-latitude meridional waveguide in the lower stratosphere that is bounded above by a reflecting surface, called a bounded wave geometry. Reanalysis data suggests that downward wave coupling during November–December has increased during the last three decades. The GEOS CCM simulation of the recent past captures the main features of downward wave coupling in the Southern Hemisphere. Consistent with the Modern Era Retrospective-Analysis for Research and Application (MERRA) dataset, wave coupling in the model maximizes during October–November when there is a bounded wave geometry configuration. However, the wave coupling in the model is stronger than in the MERRA dataset, and starts earlier and ends later in the seasonal cycle. The late season bias is caused by a bias in the timing of the stratospheric polar vortex breakup. Temporal changes in stratospheric ozone associated with past depletion and future recovery significantly impact downward wave coupling in the model. During the period of ozone depletion, the spring bounded wave geometry, which is favorable for downward wave coupling, extends into early summer, due to a delay in the vortex breakup date, and leads to increased downward wave coupling during November–December. During the period of ozone recovery, the stratospheric basic state during November–December shifts from a spring configuration back to a summer configuration, where waves are trapped in the troposphere, and leads to a decrease in downward wave coupling. Model simulations with chlorine fixed at 1960 values and increasing greenhouse gases show no significant changes in downward wave coupling and confirm that the changes in downward wave coupling in the model are caused by ozone changes. The results reveal a new mechanism wherein stratospheric ozone changes can affect the tropospheric circulation.


2016 ◽  
Author(s):  
Sandro W. Lubis ◽  
Vered Silverman ◽  
Katja Matthes ◽  
Nili Harnik ◽  
Nour-Eddine Omrani ◽  
...  

Atmosphere ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 625
Author(s):  
Ansgar Schanz ◽  
Klemens Hocke ◽  
Niklaus Kämpfer ◽  
Simon Chabrillat ◽  
Antje Inness ◽  
...  

In this study, we compare the diurnal variation in stratospheric ozone of the MACC (Monitoring Atmospheric Composition and Climate) reanalysis, ECMWF Reanalysis Interim (ERA-Interim), and the free-running WACCM (Whole Atmosphere Community Climate Model). The diurnal variation of stratospheric ozone results from photochemical and dynamical processes depending on altitude, latitude, and season. MACC reanalysis and WACCM use similar chemistry modules and calculate a similar diurnal cycle in ozone when it is caused by a photochemical variation. The results of the two model systems are confirmed by observations of the Superconducting Submillimeter-Wave Limb-Emission Sounder (SMILES) experiment and three selected sites of the Network for Detection of Atmospheric Composition Change (NDACC) at Mauna Loa, Hawaii (tropics), Bern, Switzerland (midlatitudes), and Ny-Ålesund, Svalbard (high latitudes). On the other hand, the ozone product of ERA-Interim shows considerably less diurnal variation due to photochemical variations. The global maxima of diurnal variation occur at high latitudes in summer, e.g., near the Arctic NDACC site at Ny-Ålesund, Svalbard. The local OZORAM radiometer observes this effect in good agreement with MACC reanalysis and WACCM. The sensed diurnal variation at Ny-Ålesund is up to 8% (0.4 ppmv) due to photochemical variations in summer and negligible during the dynamically dominated winter. However, when dynamics play a major role for the diurnal ozone variation as in the lower stratosphere (100–20 hPa), the reanalysis models ERA-Interim and MACC which assimilate data from radiosondes and satellites outperform the free-running WACCM. Such a domain is the Antarctic polar winter where a surprising novel feature of diurnal variation is indicated by MACC reanalysis and ERA-Interim at the edge of the polar vortex. This effect accounts for up to 8% (0.4 ppmv) in both model systems. In summary, MACC reanalysis provides a global description of the diurnal variation of stratospheric ozone caused by dynamics and photochemical variations. This is of high interest for ozone trend analysis and other research which is based on merged satellite data or measurements at different local time.


2021 ◽  
Author(s):  
Ramina Alwarda ◽  
Kristof Bognar ◽  
Kimberly Strong ◽  
Martyn Chipperfield ◽  
Sandip Dhomse ◽  
...  

<p>The Arctic winter of 2019-2020 was characterized by an unusually persistent polar vortex and temperatures in the lower stratosphere that were consistently below the threshold for the formation of polar stratospheric clouds (PSCs). These conditions led to ozone loss that is comparable to the Antarctic ozone hole. Ground-based measurements from a suite of instruments at the Polar Environment Atmospheric Research Laboratory (PEARL) in Eureka, Canada (80.05°N, 86.42°W) were used to investigate chemical ozone depletion. The vortex was located above Eureka longer than in any previous year in the 20-year dataset and lidar measurements provided evidence of polar stratospheric clouds (PSCs) above Eureka. Additionally, UV-visible zenith-sky Differential Optical Absorption Spectroscopy (DOAS) measurements showed record ozone loss in the 20-year dataset, evidence of denitrification along with the slowest increase of NO<sub>2</sub> during spring, as well as enhanced reactive halogen species (OClO and BrO). Complementary measurements of HCl and ClONO<sub>2</sub> (chlorine reservoir species) from a Fourier transform infrared (FTIR) spectrometer showed unusually low columns that were comparable to 2011, the previous year with significant chemical ozone depletion. Record low values of HNO<sub>3</sub> in the FTIR dataset are in accordance with the evidence of PSCs and a denitrified atmosphere. Estimates of chemical ozone loss were derived using passive ozone from the SLIMCAT offline chemical transport model to account for dynamical contributions to the stratospheric ozone budget.</p>


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