scholarly journals Polar Stratospheric Clouds: Satellite Observations, Processes, and Role in Ozone Depletion

2021 ◽  
Author(s):  
Ines Tritscher ◽  
Michael C. Pitts ◽  
Lamont R. Poole ◽  
Thomas Peter ◽  
Keyword(s):  
Ozone Depletion ◽  
Stratospheric Ozone ◽  
Michelson Interferometer ◽  
Orthogonal Polarization ◽  
Polar Stratospheric Clouds ◽  
Spatial And Temporal Distributions ◽  
Stratospheric Clouds ◽  
Polar Ozone ◽  
Made In

<p>The important role of polar stratospheric clouds (PSCs) in stratospheric ozone depletion during winter and spring at high latitudes has been known since the 1980s. However, contemporary observations by the spaceborne instruments MIPAS (Michelson Interferometer for Passive Atmospheric Sounding), MLS (Microwave Limb Sounder), and CALIOP (Cloud-Aerosol Lidar with Orthogonal Polarization) have brought about a comprehensive and clearer understanding of PSC spatial and temporal distributions, their conditions of existence, and the processes through which they impact polar ozone. Within the SPARC (Stratosphere-troposphere Processes And their Role in Climate) PSC initiative (PSCi), those datasets have been synthesized and discussed in depth with the result of a new vortex-wide climatology of PSC occurrence and composition. We will present our results within this vPICO together with a review of the significant progress that has been made in our understanding of PSC nucleation, related dynamical processes, and heterogeneous chlorine activation. Moreover, we have compiled different techniques for parameterizing PSCs and we will show their effects in global models.</p>

Record springtime stratospheric ozone depletion at 80°N in 2020

2021 ◽  
Author(s):  
Ramina Alwarda ◽  
Kristof Bognar ◽  
Kimberly Strong ◽  
Martyn Chipperfield ◽  
Sandip Dhomse ◽  
...  
Keyword(s):  
Ozone Depletion ◽  
Transport Model ◽  
Stratospheric Ozone ◽  
Polar Vortex ◽  
The Arctic ◽  
Optical Absorption Spectroscopy ◽  
Chemical Transport Model ◽  
Polar Stratospheric Clouds ◽  
Ozone Loss ◽  
Stratospheric Clouds

<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>

scholarly journals Stratospheric Aerosols, Polar Stratospheric Clouds, and Polar Ozone Depletion After the Mount Calbuco Eruption in 2015

2018 ◽  
Vol 123 (21) ◽  
pp. 12,308-12,331 ◽  
Author(s):  
Yunqian Zhu ◽  
Owen Brian Toon ◽  
Douglas Kinnison ◽  
V. Lynn Harvey ◽  
Michael J. Mills ◽  
...  
Keyword(s):  
Ozone Depletion ◽  
Polar Stratospheric Clouds ◽  
Stratospheric Clouds ◽  
Polar Ozone ◽  
Stratospheric Aerosols

CALIOP PSC observations from 2006-2019

2020 ◽  
Author(s):  
Michael Pitts ◽  
Lamont Poole
Keyword(s):  
Stratospheric Ozone ◽  
Polar Vortex ◽  
Theoretical Models ◽  
Volume Density ◽  
Stratospheric Aerosol ◽  
Orthogonal Polarization ◽  
Ozone Loss ◽  
In Situ Data ◽  
Spatial And Temporal Distributions ◽  
Stratospheric Clouds

<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>

scholarly journals Temperature thresholds for polar stratospheric ozone loss

2010 ◽  
Vol 10 (11) ◽  
pp. 28687-28720 ◽  
Author(s):  
K. Drdla ◽  
R. Müller
Keyword(s):  
Ozone Depletion ◽  
Stratospheric Ozone ◽  
Potential Temperature ◽  
Reaction Rates ◽  
Threshold Temperature ◽  
Temperature Threshold ◽  
Detailed Model ◽  
Significant Uptake ◽  
Stratospheric Clouds ◽  
Polar Ozone

Abstract. Low stratospheric temperatures are known to be responsible for heterogeneous chlorine activation that leads to polar ozone depletion. Here, we discuss the temperature threshold below which substantial chlorine activation occurs. We suggest that the onset of chlorine activation is dominated by reactions on cold binary aerosol particles, without formation of polar stratospheric clouds (PSCs), i.e. without significant uptake of HNO3 from the gas-phase. Using reaction rates on cold binary aerosol, a chlorine activation threshold temperature, TACL, is derived. At typical stratospheric conditions, TACL is similar in value to TNAT the highest temperature at which nitric acid trihydrate (NAT) can theoretically condense to form PSCs. TACL is still in use as parameterization for the threshold temperature for the onset of chlorine activation. However, perturbations can cause TACL to differ from TNAT: TACL is dependent upon H2O, potential temperature, and the sulphate aerosol loading, but unlike TNAT is not dependent upon HNO3. A parameterization of TACL is provided here, allowing it to be calculated over a comprehensive range of stratospheric conditions. Although considering TACL as a proxy for chlorine activation can be no substitute for a detailed model calculation, TACL provides a more accurate description of the temperature conditions necessary for polar ozone depletion than TNAT and can readily be used in place of TNAT.

scholarly journals Denitrification, dehydration and ozone loss during the Arctic winter 2015/2016

2017 ◽  
Author(s):  
Farahnaz Khosrawi ◽  
Oliver Kirner ◽  
Björn-Martin Sinnhuber ◽  
Sören Johansson ◽  
Michael Höpfner ◽  
...  
Keyword(s):  
Atmospheric Chemistry ◽  
Stratospheric Ozone ◽  
Satellite Observations ◽  
The Arctic ◽  
Cold Pool ◽  
Polar Stratospheric Clouds ◽  
Airborne Measurements ◽  
Ozone Loss ◽  
Polar Stratosphere ◽  
Stratospheric Clouds

Abstract. The Arctic winter 2015/2016 was one of the coldest stratospheric winters in recent years. A stable vortex formed by early December and the early winter was exceptionally cold. Cold pool temperatures dropped below the Nitric Acid Trihydrate (NAT) existence temperature of about 195 K, thus allowing Polar Stratospheric Clouds (PSCs) to form. The low temperatures in the polar stratosphere persisted until early March allowing chlorine activation and catalytic ozone destruction. Satellite observations indicate that sedimentation of PSC particles led to denitrification as well as dehydration of stratospheric layers. Model simulations of the Arctic winter 2015/2016 nudged toward European Center for Medium-Range Weather Forecasts (ECMWF) analyses data were performed with the atmospheric chemistry–climate model ECHAM5/MESSy Atmospheric Chemistry (EMAC) for the Polar Stratosphere in a Changing Climate (POLSTRACC) campaign. POLSTRACC is a High Altitude and LOng Range Research Aircraft (HALO) mission aimed at the investigation of the structure, composition and evolution of the Arctic Upper Troposphere and Lower Stratosphere (UTLS). The chemical and physical processes involved in Arctic stratospheric ozone depletion, transport and mixing processes in the UTLS at high latitudes, polar stratospheric clouds as well as cirrus clouds are investigated. In this study an overview of the chemistry and dynamics of the Arctic winter 2015/2016 as simulated with EMAC is given. Further, chemical-dynamical processes such as denitrification, dehydration and ozone loss during the Arctic winter 2015/2016 are investigated. Comparisons to satellite observations by the Aura Microwave Limb Sounder (Aura/MLS) as well as to airborne measurements with the Gimballed Limb Observer for Radiance Imaging of the Atmosphere (GLORIA) performed on board of HALO during the POLSTRACC campaign show that the EMAC simulations are in fairly good agreement with observations. We derive a maximum polar stratospheric O3 loss of ~ 2 ppmv or 100 DU in terms of column in mid March. The stratosphere was denitrified by about 8 ppbv HNO3 and dehydrated by about 1 ppmv H2O in mid to end of February. While ozone loss was quite strong, but not as strong as in 2010/2011, denitrification and dehydration were so far the strongest observed in the Arctic stratosphere in the at least past 10 years.

scholarly journals Nucleation of nitric acid hydrates in Polar Stratospheric Clouds by meteoric material

2017 ◽  
Author(s):  
Alexander D. James ◽  
James S. A. Brooke ◽  
Thomas P. Mangan ◽  
Thomas F. Whale ◽  
John M. C. Plane ◽  
...  
Keyword(s):  
Nitric Acid ◽  
Heterogeneous Nucleation ◽  
Ozone Depletion ◽  
Mode Of Action ◽  
Polar Stratospheric Clouds ◽  
Water Ice ◽  
Meteoric Smoke ◽  
Polar Stratosphere ◽  
Stratospheric Clouds ◽  
Meteoric Material

Abstract. Heterogeneous nucleation of crystalline nitric acid hydrates in Polar Stratospheric Clouds (PSCs) enhances ozone depletion. However, the identity and mode of action of the particles responsible for nucleation remains unknown. It has been suggested that meteoric material may trigger nucleation of nitric acid trihydrate (NAT), but this has never been directly demonstrated in the laboratory. Meteoric material is present in two forms in the stratosphere, smoke which results from the ablation and re-condensation of vapours, and fragments which result from the disruption of meteoroids entering the atmosphere. Here we show that analogues of both materials have a capacity to nucleate nitric acid hydrates. In combination with estimates from a global model of the amount of meteoric smoke and fragments in the polar stratosphere we show that meteoric material probably accounts for NAT observations in early season polar stratospheric clouds in the absence of water ice.

scholarly journals Bias determination and precision validation of ozone profiles from MIPAS-Envisat retrieved with the IMK-IAA processor

2007 ◽  
Vol 7 (13) ◽  
pp. 3639-3662 ◽  
Author(s):  
T. Steck ◽  
T. von Clarmann ◽  
H. Fischer ◽  
B. Funke ◽  
N. Glatthor ◽  
...  
Keyword(s):  
Stratospheric Ozone ◽  
Michelson Interferometer ◽  
High Spectral Resolution ◽  
Vapor Concentration ◽  
Atmospheric Sounding ◽  
Mean Differences ◽  
Microwave Radiometers ◽  
Vertical Ozone ◽  
Vertical Ozone Profiles ◽  
Polar Ozone

Abstract. This paper characterizes vertical ozone profiles retrieved with the IMK-IAA (Institute for Meteorology and Climate Research, Karlsruhe – Instituto de Astrofisica de Andalucia) science-oriented processor from high spectral resolution data (until March 2004) measured by the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) aboard the environmental satellite Envisat. Bias determination and precision validation is performed on the basis of correlative measurements by ground-based lidars, Fourier transform infrared spectrometers, and microwave radiometers as well as balloon-borne ozonesondes, the balloon-borne version of MIPAS, and two satellite instruments (Halogen Occultation Experiment and Polar Ozone and Aerosol Measurement III). Percentage mean differences between MIPAS and the comparison instruments for stratospheric ozone are generally within ±10%. The precision in this altitude region is estimated at values between 5 and 10% which gives an accuracy of 15 to 20%. Below 18 km, the spread of the percentage mean differences is larger and the precision degrades to values of more than 20% depending on altitude and latitude. The main reason for the degraded precision at low altitudes is attributed to undetected thin clouds which affect MIPAS retrievals, and to the influence of uncertainties in the water vapor concentration.

scholarly journals Northern Hemisphere Stratospheric Ozone Depletion Caused by Solar Proton Events: The Role of the Polar Vortex

2018 ◽  
Vol 45 (4) ◽  
pp. 2115-2124 ◽  
Author(s):  
M. H. Denton ◽  
R. Kivi ◽  
T. Ulich ◽  
M. A. Clilverd ◽  
C. J. Rodger ◽  
...  
Keyword(s):  
Northern Hemisphere ◽  
Ozone Depletion ◽  
Stratospheric Ozone ◽  
Polar Vortex ◽  
Solar Proton ◽  
Stratospheric Ozone Depletion ◽  
Solar Proton Events
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