scholarly journals Antarctic ozone variability inside the polar vortex estimated from balloon measurements

2014 ◽  
Vol 14 (1) ◽  
pp. 217-229 ◽  
Author(s):  
M. C. Parrondo ◽  
M. Gil ◽  
M. Yela ◽  
B. J. Johnson ◽  
H. A. Ochoa

Abstract. Thirteen years of ozone soundings at the Antarctic Belgrano II station (78° S, 34.6° W) have been analysed to establish a climatology of stratospheric ozone and temperature over the area. The station is inside the polar vortex during the period of development of chemical ozone depletion. Weekly periodic profiles provide a suitable database for seasonal characterization of the evolution of stratospheric ozone, especially valuable during wintertime, when satellites and ground-based instruments based on solar radiation are not available. The work is focused on ozone loss rate variability (August–October) and its recovery (November–December) at different layers identified according to the severity of ozone loss. The time window selected for the calculations covers the phase of a quasi-linear ozone reduction, around day 220 (mid-August) to day 273 (end of September). Decrease of the total ozone column over Belgrano during spring is highly dependent on the meteorological conditions. Largest depletions (up to 59%) are reached in coldest years, while warm winters exhibit significantly lower ozone loss (20%). It has been found that about 11% of the total O3 loss, in the layer where maximum depletion occurs, takes place before sunlight has arrived, as a result of transport to Belgrano of air from a somewhat lower latitude, near the edge of the polar vortex, providing evidence of mixing inside the vortex. Spatial homogeneity of the vortex has been examined by comparing Belgrano results with those previously obtained for South Pole station (SPS) for the same altitude range and for 9 yr of overlapping data. Results show more than 25% higher ozone loss rate at SPS than at Belgrano. The behaviour can be explained taking into account (i) the transport to both stations of air from a somewhat lower latitude, near the edge of the polar vortex, where sunlight reappears sooner, resulting in earlier depletion of ozone, and (ii) the accumulated hours of sunlight, which become much greater at the South Pole after the spring equinox. According to the variability of the ozone hole recovery, a clear connection between the timing of the breakup of the vortex and the monthly ozone content was found. Minimum ozone concentration of 57 DU in the 12–24 km layer remained in November, when the vortex is more persistent, while in years when the final stratospheric warming took place "very early", mean integrated ozone rose by up to 160–180 DU.

2013 ◽  
Vol 13 (6) ◽  
pp. 15663-15695
Author(s):  
M. C. Parrondo ◽  
M. Gil ◽  
M. Yela ◽  
B. J. Johnson ◽  
H. A. Ochoa

Abstract. 13 yr of ozonesoundings at the Antarctic Belgrano II station (78° S, 34.6° W) have been analyzed to establish a climatology of stratospheric ozone and temperature over the area. The station is inside the polar vortex during the period of development of chemical ozone depletion. Weekly periodic profiles provide a suitable database for seasonal characterization of the evolution of stratospheric ozone, especially valuable during winter time when satellites and ground-based instruments based on solar radiation are lacking. The work is focused on ozone loss rate variability (August–October) and its recovery (November–December) at different layers identified according to the severity of ozone loss. The time window selected for the calculations covers the phase of a quasi-linear ozone reduction, about day 220 (mid August) to day 273 (end of September). Decrease of the total ozone column over Belgrano during spring is highly dependent on the meteorological conditions. Largest depletions (up to 59%) are reached in coldest years while warms winters exhibit significantly lower ozone loss (20%). It has been found that about 11% of the total O3 loss in the layer where maximum depletion occurs takes place before the sun has arrived as a result of transport of lower latitude air masses, providing evidence of mixing inside the vortex. Spatial homogeneity of the vortex has been examined by comparing Belgrano results with those previously obtained for South Pole Station (SPS) for the same altitude range and for 9 yr of overlapping data. Unexpected results show more than 25% larger ozone loss rate at SPS than at Belgrano. It has been found that the accumulated hours of sunlight are the dominant factor driving the ozone loss rate. According to the variability of the ozone-hole recovery, a clear connection between the timing of the breakup of the vortex and the monthly ozone content was found. Minimum ozone concentration of 57 DU in the 12–24 km layer remained in November for the longest vortex, while years when the final stratospheric warming took "very early", mean integrated ozone rises up to 160–180 DU.


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>


2018 ◽  
Vol 9 (1) ◽  
Author(s):  
Jiankai Zhang ◽  
Wenshou Tian ◽  
Fei Xie ◽  
Martyn P. Chipperfield ◽  
Wuhu Feng ◽  
...  

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.


2003 ◽  
Vol 3 (2) ◽  
pp. 395-402 ◽  
Author(s):  
J.-U. Grooß ◽  
R. Müller

Abstract. Current stratospheric chemical model simulations underestimate substantially the large ozone loss rates that are derived for the Arctic from ozone sondes for January of some years. Until now, no explanation for this discrepancy has been found. Here, we examine the influence of intrusions of mid-latitude air into the polar vortex on these ozone loss estimates. This study focuses on the winter 1991/92, because during this winter the discrepancy between simulated and experimentally derived ozone loss rates is reported to be the largest. Also during the considered period the vortex was disturbed by a strong warming event with large-scale intrusions of mid-latitude air into the polar vortex, which is quite unusual for this time of the year. The study is based on simulations performed with the Chemical Lagrangian Model of the Stratosphere (CLaMS). Two methods for determination the ozone loss are investigated, the so-called vortex average approach and the Match method. The simulations for January 1992 show that the intrusions induce a reduction of vortex average ozone mixing ratio corresponding to a systematic offset of the ozone loss rate of about 12 ppb per day. This should be corrected for in the vortex average method. The simulations further suggest, that these intrusions do not cause a significant bias for the Match method due to effective quality control measures in the Match technique.


2002 ◽  
Vol 2 (6) ◽  
pp. 2489-2506
Author(s):  
J.-U. Grooß ◽  
R. Müller

Abstract. Current stratospheric chemical model simulations underestimate substantially the large ozone loss rates that are derived for the Arctic from ozone sondes for January of some years. Until now, no explanation for this discrepancy has been found. Here, we examine the influence of intrusions of mid-latitude air into the polar vortex on these ozone loss estimates. This study focuses on the winter 1991/92. It is based on simulations performed with the Chemical Lagrangian Model of the Stratosphere (CLaMS). The simulations for January 1992 show that the intrusions induce a reduction of vortex average ozone mixing ratio corresponding to a systematic offset of the ozone loss rate of about 12 ppb per day. Further, the results of the Match method are influenced by the intrusions, since the intruded air masses are deformed and reach dimensions below the Match radius. From our calculations we deduce a systematic offset of the Match ozone loss rate by about 10 ppb/day, which may explain about 28% of the published discrepancy between Match and box model simulations for the winter 1991/92.


2005 ◽  
Vol 5 (5) ◽  
pp. 1399-1407 ◽  
Author(s):  
U. Raffalski ◽  
G. Hochschild ◽  
G. Kopp ◽  
J. Urban

Abstract. We present ozone measurements from the millimetre wave radiometer installed at the Swedish Institute of Space Physics (Institutet för rymdfysik, IRF) in Kiruna (67.8° N, 20.4° E, 420 m asl). Nearly continuous operation in the winter of 2002/2003 allows us to give an overview of ozone evolution in the stratosphere between 15 and 55 km. In this study we present a detailed analysis of the Arctic winter 2002/2003. By means of a methodology using equivalent latitudes we investigate the meteorological processes in the stratosphere during the entire winter/spring period. During the course of the winter strong mixing into the vortex took place in the middle and upper stratosphere as a result of three minor and one major warming event, but no evidence was found for significant mixing in the lower stratosphere. Ozone depletion in the lower stratosphere during this winter was estimated by measurements on those days when Kiruna was well inside the Arctic polar vortex. The days were carefully chosen using a definition of the vortex edge based on equivalent latitudes. At the 475 K isentropic level a cumulative ozone loss of about 0.5 ppmv was found starting in January and lasting until mid-March. The early ozone loss is probably a result of the very cold temperatures in the lower stratosphere in December and the geographical extension of the vortex to lower latitudes where solar irradiation started photochemical ozone loss in the pre-processed air. In order to correct for dynamic effects of the ozone variation due to diabatic subsidence of air masses inside the vortex, we used N2O measurements from the Odin satellite for the same time period. The derived ozone loss in the lower stratosphere between mid-December and mid-March varies between 1.1±0.1 ppmv on the 150 ppbv N2O isopleth and 1.7±0.1 ppmv on the 50 ppbv N2O isopleth.


2020 ◽  
Author(s):  
Michael Pitts ◽  
Lamont Poole

<p>Even though the role of polar stratospheric clouds (PSCs) in stratospheric ozone depletion is well established, important questions remain unanswered that have limited our understanding of PSC processes and how to accurately represent them in global models.  This has called into question our prognostic capabilities for future ozone loss in a changing climate.  A more complete picture of PSC processes on polar vortex-wide scales has emerged from the CALIOP (Cloud-Aerosol Lidar with Orthogonal Polarization) instrument on the CALIPSO (Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations) satellite that has been observing PSCs at latitudes up to 82 degrees in both hemispheres since June 2006.  In this paper, we present a state-of-the-art climatology of PSC spatial and temporal distributions and particle composition constructed from the more than 14-year CALIOP spaceborne lidar dataset.  The climatology also includes estimates of particulate surface area density and volume density to facilitate comparisons with in situ data and measurements by other remote sensors, as well as with theoretical models relating PSCs to heterogeneous chemical processing and ozone loss. Finally, we compare the CALIOP PSC data record with the 1979-1989 SAM II (Stratospheric Aerosol Measurement II) solar occultation PSC record to investigate possible multi-decadal changes in PSC occurrence.</p>


2019 ◽  
Vol 19 (1) ◽  
pp. 577-601 ◽  
Author(s):  
Debora Griffin ◽  
Kaley A. Walker ◽  
Ingo Wohltmann ◽  
Sandip S. Dhomse ◽  
Markus Rex ◽  
...  

Abstract. Stratospheric ozone loss inside the Arctic polar vortex for the winters between 2004–2005 and 2012–2013 has been quantified using measurements from the space-borne Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE-FTS). For the first time, an evaluation has been performed of six different ozone loss estimation methods based on the same single observational dataset to determine the Arctic ozone loss (mixing ratio loss profiles and the partial-column ozone losses between 380 and 550 K). The methods used are the tracer-tracer correlation, the artificial tracer correlation, the average vortex profile descent, and the passive subtraction with model output from both Lagrangian and Eulerian chemical transport models (CTMs). For the tracer-tracer, the artificial tracer, and the average vortex profile descent approaches, various tracers have been used that are also measured by ACE-FTS. From these seven tracers investigated (CH4, N2O, HF, OCS, CFC-11, CFC-12, and CFC-113), we found that CH4, N2O, HF, and CFC-12 are the most suitable tracers for investigating polar stratospheric ozone depletion with ACE-FTS v3.5. The ozone loss estimates (in terms of the mixing ratio as well as total column ozone) are generally in good agreement between the different methods and among the different tracers. However, using the average vortex profile descent technique typically leads to smaller maximum losses (by approximately 15–30 DU) compared to all other methods. The passive subtraction method using output from CTMs generally results in slightly larger losses compared to the techniques that use ACE-FTS measurements only. The ozone loss computed, using both measurements and models, shows the greatest loss during the 2010–2011 Arctic winter. For that year, our results show that maximum ozone loss (2.1–2.7 ppmv) occurred at 460 K. The estimated partial-column ozone loss inside the polar vortex (between 380 and 550 K) using the different methods is 66–103, 61–95, 59–96, 41–89, and 85–122 DU for March 2005, 2007, 2008, 2010, and 2011, respectively. Ozone loss is difficult to diagnose for the Arctic winters during 2005–2006, 2008–2009, 2011–2012, and 2012–2013, because strong polar vortex disturbance or major sudden stratospheric warming events significantly perturbed the polar vortex, thereby limiting the number of measurements available for the analysis of ozone loss.


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