scholarly journals Comments on "Small-scale variability of stratospheric ozone during the SSW 2018/2019 observed at Ny-Ålesund, Svalbard" by Schranz et al. (2020).

2020 ◽  
Keyword(s):  
Stratospheric Ozone ◽  
Small Scale

scholarly journals Observations of filamentary structures near the vortex edge in the Arctic winter lower stratosphere

2013 ◽  
Vol 13 (21) ◽  
pp. 10859-10871 ◽  
Author(s):  
C. Kalicinsky ◽  
J.-U. Grooß ◽  
G. Günther ◽  
J. Ungermann ◽  
J. Blank ◽  
...  
Keyword(s):  
Cross Sections ◽  
Transport Model ◽  
Stratospheric Ozone ◽  
Polar Vortex ◽  
Lagrangian Model ◽  
The Arctic ◽  
Small Scale ◽  
Air Mass ◽  
Mixing Ratios ◽  
Passive Tracers

Abstract. The CRISTA-NF (Cryogenic Infrared Spectrometers and Telescope for the Atmosphere – New Frontiers) instrument is an airborne infrared limb sounder operated aboard the Russian research aircraft M55-Geophysica. The instrument successfully participated in a large Arctic aircraft campaign within the RECONCILE (Reconciliation of essential process parameters for an enhanced predictability of Arctic stratospheric ozone loss and its climate interactions) project in Kiruna (Sweden) from January to March 2010. This paper concentrates on the measurements taken during one flight of the campaign, which took place on 2 March in the vicinity of the polar vortex. We present two-dimensional cross-sections of derived volume mixing ratios for the trace gases CFC-11, O3, and ClONO2 with an unprecedented vertical resolution of about 500 to 600 m for a large part of the observed altitude range (≈ 6–19 km) and a dense horizontal sampling along flight direction of ≈ 15 km. The trace gas distributions show several structures, for example a part of the polar vortex and a vortex filament, which can be identified by means of O3–CFC-11 tracer–tracer correlations. The observations made during this flight are interpreted using the chemistry and transport model CLaMS (Chemical Lagrangian Model of the Stratosphere). Comparisons of the observations with the model results are used to assess the performance of the model with respect to advection, mixing, and the chemistry in the polar vortex. These comparisons confirm the capability of CLaMS to reproduce even very small-scale structures in the atmosphere, which partly have a vertical extent of only 1 km. Based on the good agreement between simulation and observation, we use artificial (passive) tracers, which represent different air mass origins (e.g. vortex, tropics), to further analyse the CRISTA-NF observations in terms of the composition of air mass origins. These passive tracers clearly illustrate the observation of filamentary structures that include tropical air masses. A characteristic of the Arctic winter 2009/10 was a sudden stratospheric warming in December that led to a split of the polar vortex. The vortex re-established at the end of December. Our passive tracer simulations suggest that large parts of the re-established vortex consisted to about 45% of high- and mid-latitude air.

scholarly journals Stratospheric controlled perturbation experiment: a small-scale experiment to improve understanding of the risks of solar geoengineering

2014 ◽  
Vol 372 (2031) ◽  
pp. 20140059 ◽  
Author(s):  
John A. Dykema ◽  
David W. Keith ◽  
James G. Anderson ◽  
Debra Weisenstein
Keyword(s):  
Risk Assessment ◽  
Large Scale ◽  
Current Knowledge ◽  
Stratospheric Ozone ◽  
Full Range ◽  
Stratospheric Aerosol ◽  
Small Scale ◽  
Solar Radiation Management ◽  
Perturbation Experiment ◽  
Radiation Management

Although solar radiation management (SRM) through stratospheric aerosol methods has the potential to mitigate impacts of climate change, our current knowledge of stratospheric processes suggests that these methods may entail significant risks. In addition to the risks associated with current knowledge, the possibility of ‘unknown unknowns’ exists that could significantly alter the risk assessment relative to our current understanding. While laboratory experimentation can improve the current state of knowledge and atmospheric models can assess large-scale climate response, they cannot capture possible unknown chemistry or represent the full range of interactive atmospheric chemical physics. Small-scale, in situ experimentation under well-regulated circumstances can begin to remove some of these uncertainties. This experiment—provisionally titled the stratospheric controlled perturbation experiment—is under development and will only proceed with transparent and predominantly governmental funding and independent risk assessment. We describe the scientific and technical foundation for performing, under external oversight, small-scale experiments to quantify the risks posed by SRM to activation of halogen species and subsequent erosion of stratospheric ozone. The paper's scope includes selection of the measurement platform, relevant aspects of stratospheric meteorology, operational considerations and instrument design and engineering.

scholarly journals Small-scale variability of stratospheric ozone during the SSW 2018/2019 observed at Ny-Ålesund, Svalbard

2019 ◽  
Author(s):  
Franziska Schranz ◽  
Jonas Hagen ◽  
Gunter Stober ◽  
Klemens Hocke ◽  
Axel Murk ◽  
...  
Keyword(s):  
Water Vapour ◽  
Planetary Wave ◽  
Stratospheric Ozone ◽  
Elevation Angle ◽  
Wave Activity ◽  
The Arctic ◽  
Wave Number ◽  
Small Scale ◽  
Horizontal Distance ◽  
Meridional Transport

Abstract. Middle atmospheric ozone, water vapour and zonal and meridional wind profiles have been measured with the two ground-based microwave radiometers GROMOS-C and MIAWARA-C. The instruments are located at the Arctic research base AWIPEV at Ny-Ålesund, Svalbard (79° N, 12° E) since September 2015. GROMOS-C measures ozone spectra in the four cardinal directions with an elevation angle of 22°. This means that the probed airmasses at an altitude of 3 hPa (37 km) have a horizontal distance of 92 km to Ny-Ålesund. We retrieve four separate ozone profiles along the lines of sight and calculate daily mean horizontal ozone gradients which allow us to investigate the small-scale spatial variability of ozone above Ny-Ålesund. In winter 2018/2019 a major sudden stratospheric warming (SSW) took place with the central date at 2 January. We present the ozone, water vapour and wind measurements of the winter 2018/2019 and discuss the signatures of the SSW in a global context. We further present the evolution of the ozone gradients at Ny-Ålesund and link it to the planetary wave activity. At 3 hPa we find a distinct seasonal variation of the ozone gradients. In October and March a strong polar vortex leads to ozone decreases towards the pole. In November the amplitudes of the planetary waves grow until they break in the end of December and an SSW takes place. From November until February the ozone gradients mostly point to higher latitudes and the magnitude is smaller than in October and March. We attribute this to the planetary wave activity of wave number 1 and 2 which enabled meridional transport. The MERRA-2 reanalysis and the SD-WACCM model are able to capture the small-scale ozone variability and its seasonal changes.

NDACC Lidar Validation Activities in Europe

2020 ◽  
Author(s):  
Robin Wing ◽  
Wolfgang Steinbrecht ◽  
Sophie Godin-Beekmann ◽  
Thomas J. McGee ◽  
John Sullivan ◽  
...  
Keyword(s):  
Stratospheric Ozone ◽  
Uncertainty Budget ◽  
Small Scale ◽  
Statistical Techniques ◽  
Ncep Reanalysis ◽  
Broadband Emission ◽  
Meteorological Observatory ◽  
Intercomparison Exercises ◽  
Good Agreement ◽  
Balloon Measurements

<p>Recent intercomparison exercises have been conducted at two European NDACC lidar sites.  The mobile NASA Stratospheric Ozone Lidar (NASA STROZ) was present for a two part validation campaign at the Observatoire de Haute-Provence (43.93 N, 5.71 E) in July 2017 and March 2018 and at the Hohenpeißenberg Meteorological Observatory (47.80 N, 11.00 E) in March 2019.  Lidar profiles of ozone and temperature were compared with local radiosondes and ozonesondes; satellite profiles from local overpasses of Sounding of the Atmosphere by Broadband Emission Radiometry instrument (SABER) and Microwave Limb Sounder (MLS); and NCEP reanalysis. There is overall good agreement between all the lidar instruments and the balloon measurements, particularly in the reproduction of small scale features, during all three phases of the European campaign.  </p><p>We have conducted a detailed correlational study of all instruments involved in the campaign and have rigorously evaluated the uncertainty budget of each instrument.  We will discuss the strengths and drawbacks of different statistical techniques for evaluating coincident ozone and temperature measurements and compare how our estimates of instrument uncertainty compare to the observed variance in the data.</p>

scholarly journals Arctic stratospheric dehydration – Part 2: Microphysical modeling

2014 ◽  
Vol 14 (7) ◽  
pp. 3231-3246 ◽  
Author(s):  
I. Engel ◽  
B. P. Luo ◽  
S. M. Khaykin ◽  
F. G. Wienhold ◽  
H. Vömel ◽  
...  
Keyword(s):  
Water Vapor ◽  
Nitric Acid ◽  
Stratospheric Ozone ◽  
Chemical Species ◽  
Ice Nucleation ◽  
The Arctic ◽  
Small Scale ◽  
Synoptic Scale ◽  
Particle Sedimentation ◽  
Initial Water

Abstract. Large areas of synoptic-scale ice PSCs (polar stratospheric clouds) distinguished the Arctic winter 2009/2010 from other years and revealed unprecedented evidence of water redistribution in the stratosphere. A unique snapshot of water vapor repartitioning into ice particles was obtained under extremely cold Arctic conditions with temperatures around 183 K. Balloon-borne, aircraft and satellite-based measurements suggest that synoptic-scale ice PSCs and concurrent reductions and enhancements in water vapor are tightly linked with the observed de- and rehydration signatures, respectively. In a companion paper (Part 1), water vapor and aerosol backscatter measurements from the RECONCILE (Reconciliation of essential process parameters for an enhanced predictability of Arctic stratospheric ozone loss and its climate interactions) and LAPBIAT-II (Lapland Atmosphere–Biosphere Facility) field campaigns have been analyzed in detail. This paper uses a column version of the Zurich Optical and Microphysical box Model (ZOMM) including newly developed NAT (nitric acid trihydrate) and ice nucleation parameterizations. Particle sedimentation is calculated in order to simulate the vertical redistribution of chemical species such as water and nitric acid. Despite limitations given by wind shear and uncertainties in the initial water vapor profile, the column modeling unequivocally shows that (1) accounting for small-scale temperature fluctuations along the trajectories is essential in order to reach agreement between simulated optical cloud properties and observations, and (2) the use of recently developed heterogeneous ice nucleation parameterizations allows the reproduction of the observed signatures of de- and rehydration. Conversely, the vertical redistribution of water measured cannot be explained in terms of homogeneous nucleation of ice clouds, whose particle radii remain too small to cause significant dehydration.

scholarly journals Small-scale variability of stratospheric ozone during the sudden stratospheric warming 2018/2019 observed at Ny-Ålesund, Svalbard

2020 ◽  
Vol 20 (18) ◽  
pp. 10791-10806 ◽  
Author(s):  
Franziska Schranz ◽  
Jonas Hagen ◽  
Gunter Stober ◽  
Klemens Hocke ◽  
Axel Murk ◽  
...  
Keyword(s):  
Water Vapour ◽  
Planetary Wave ◽  
Stratospheric Ozone ◽  
Elevation Angle ◽  
Wave Activity ◽  
The Arctic ◽  
Small Scale ◽  
Horizontal Distance ◽  
Stratospheric Warming ◽  
Sudden Stratospheric Warming

Abstract. Middle atmospheric ozone, water vapour and zonal and meridional wind profiles have been measured with the two ground-based microwave radiometers GROMOS-C and MIAWARA-C. The instruments have been located at the Arctic research base AWIPEV at Ny-Ålesund, Svalbard (79∘ N, 12∘ E), since September 2015. GROMOS-C measures ozone spectra in the four cardinal directions with an elevation angle of 22∘. This means that the probed air masses at an altitude of 3 hPa (37 km) have a horizontal distance of 92 km to Ny-Ålesund. We retrieve four separate ozone profiles along the lines of sight and calculate daily mean horizontal ozone gradients which allow us to investigate the small-scale spatial variability of ozone above Ny-Ålesund. We present the evolution of the ozone gradients at Ny-Ålesund during winter 2018/2019, when a major sudden stratospheric warming (SSW) took place with the central date at 2 January, and link it to the planetary wave activity. We further analyse the SSW and discuss our ozone and water vapour measurements in a global context. At 3 hPa we find a distinct seasonal variation of the ozone gradients. The strong polar vortex during October and March results in a decreasing ozone volume mixing ratio towards the pole. In November the amplitudes of the planetary waves grow until they break in the end of December and an SSW takes place. From November until February ozone increases towards higher latitudes and the magnitude of the ozone gradients is smaller than in October and March. We attribute this to the planetary wave activity of wave numbers 1 and 2 which enabled meridional transport. The MERRA-2 reanalysis and the SD-WACCM model are able to capture the small-scale ozone variability and its seasonal changes.

scholarly journals Arctic stratospheric dehydration – Part 2: Microphysical modeling

2013 ◽  
Vol 13 (10) ◽  
pp. 27163-27200 ◽  
Author(s):  
I. Engel ◽  
B. P. Luo ◽  
S. M. Khaykin ◽  
F. G. Wienhold ◽  
H. Vömel ◽  
...  
Keyword(s):  
Water Vapor ◽  
Nitric Acid ◽  
Stratospheric Ozone ◽  
Chemical Species ◽  
Companion Paper ◽  
Ice Nucleation ◽  
The Arctic ◽  
Small Scale ◽  
Synoptic Scale ◽  
Particle Sedimentation

Abstract. Large areas of synoptic-scale ice PSCs (Polar Stratospheric Clouds) distinguished the Arctic winter 2009/2010 from other years and revealed unprecedented evidence of water redistribution in the stratosphere. A unique snapshot of water vapor repartitioning into ice particles was observed under extremely cold Arctic conditions with temperatures around 183 K. Balloon-borne, aircraft and satellite-based measurements suggest that synoptic-scale ice PSCs and concurrent reductions and enhancements in water vapor are tightly linked with the observed de- and rehydration signatures, respectively. In a companion paper (Part 1), water vapor and aerosol backscatter measurements from the RECONCILE (Reconciliation of essential process parameters for an enhanced predictability of Arctic stratospheric ozone loss and its climate interactions) and LAPBIAT-II (Lapland Atmosphere-Biosphere Facility) field campaigns have been analyzed in detail. This paper uses a column version of the Zurich Optical and Microphysical box Model (ZOMM) including newly developed NAT (Nitric Acid Trihydrate) and ice nucleation parameterizations. Particle sedimentation is calculated in order to simulate the vertical redistribution of chemical species such as water and nitric acid. Accounting for small-scale temperature fluctuations along the trajectory is essential to reach agreement between simulated optical cloud properties and observations. Whereas modeling only homogeneous nucleation causes the formation of ice clouds with particle radii too small to explain the measured vertical redistribution of water, we show that the use of recently developed heterogeneous ice nucleation parameterizations allows the model to quantitatively reproduce the observed signatures of de- and rehydration.

scholarly journals Small-scale transport structures in the Arctic winter 2009/2010

2013 ◽  
Vol 13 (4) ◽  
pp. 10463-10498 ◽  
Author(s):  
C. Kalicinsky ◽  
J.-U. Grooß ◽  
G. Günther ◽  
J. Ungermann ◽  
J. Blank ◽  
...  
Keyword(s):  
Cross Sections ◽  
Transport Model ◽  
Stratospheric Ozone ◽  
Polar Vortex ◽  
Lagrangian Model ◽  
The Arctic ◽  
Small Scale ◽  
Model Concept ◽  
Mixing Ratios ◽  
Flight Direction

Abstract. The CRISTA-NF (Cryogenic Infrared Spectrometers and Telescope for the Atmosphere – New Frontiers) instrument is an airborne infrared limb sounder operated aboard the Russian research aircraft M55-Geophysica. The instrument successfully participated in a large Arctic aircraft campaign within the RECONCILE (Reconciliation of essential process parameters for an enhanced predictability of Arctic stratospheric ozone loss and its climate interactions) project from January to March 2010 in Kiruna, Sweden. This paper concentrates on the measurements during one flight of the campaign, which took place on 2 March in the vicinity of the polar vortex. We present two-dimensional cross-sections of volume mixing ratios for the trace gases CFC-11, O3, and ClONO2 with an unprecedented vertical resolution of about 500 to 600 m for a large part of the observed altitude range and a dense horizontal sampling along flight direction of ≈ 15 km. The trace gas distributions show several structures like the polar vortex and filaments composed of air masses of different origin. The situation during the analysed flight is simulated by the chemistry and transport model CLaMS (Chemical Lagrangian Model of the Stratosphere) and compared with the measurements to assess the performance of the model with respect to advection, mixing, and the chemistry in the polar vortex. These comparisons confirm the capability of CLaMS to reproduce even very small-scale structures in the atmosphere. Based on the good agreement between simulation and observation, we use a model concept utilising artificial tracers to further analyse the CRISTA-NF observations in terms of air mass origin. A characteristic of the Arctic winter 2009/10 was a sudden stratospheric warming in early December that led to a split of the polar vortex. The vortex re-established at the end of December. Our passive tracer simulations suggest that large parts of the re-established vortex consisted to about 45% of high- and mid-latitude air.

Reasons to strike first

2019 ◽  
Vol 42 ◽  
Author(s):  
William Buckner ◽  
Luke Glowacki
Keyword(s):  
Intergroup Conflict ◽  
Small Scale

Abstract De Dreu and Gross predict that attackers will have more difficulty winning conflicts than defenders. As their analysis is presumed to capture the dynamics of decentralized conflict, we consider how their framework compares with ethnographic evidence from small-scale societies, as well as chimpanzee patterns of intergroup conflict. In these contexts, attackers have significantly more success in conflict than predicted by De Dreu and Gross's model. We discuss the possible reasons for this disparity.

Exploring Coronal Structures with SOHO

2000 ◽  
Vol 179 ◽  
pp. 403-406
Author(s):  
M. Karovska ◽  
B. Wood ◽  
J. Chen ◽  
J. Cook ◽  
R. Howard
Keyword(s):  
Solar Corona ◽  
Image Enhancement ◽  
Coronal Mass Ejections ◽  
Dynamical Evolution ◽  
Small Scale ◽  
Low Contrast ◽  
Contrast Structures ◽  
Scale Structures ◽  
Small Scale Structures ◽  
Coronal Structures

AbstractWe applied advanced image enhancement techniques to explore in detail the characteristics of the small-scale structures and/or the low contrast structures in several Coronal Mass Ejections (CMEs) observed by SOHO. We highlight here the results from our studies of the morphology and dynamical evolution of CME structures in the solar corona using two instruments on board SOHO: LASCO and EIT.

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