scholarly journals Antarctic air over New Zealand following vortex breakdown in 1998

2003 ◽  
Vol 21 (11) ◽  
pp. 2175-2183 ◽  
Author(s):  
J. Ajtic ◽  
B. J. Connor ◽  
C. E. Randall ◽  
B. N. Lawrence ◽  
G. E. Bodeker ◽  
...  
Keyword(s):  
New Zealand ◽  
Middle Atmosphere ◽  
Vortex Breakdown ◽  
Potential Temperature ◽  
Polar Vortex ◽  
Atmospheric Composition ◽  
Composition And Structure ◽  
Ozone Profile ◽  
Antarctic Polar Vortex ◽  
The Antarctic

Abstract. An ozonesonde profile over the Network for Detection of Stratospheric Change (NDSC) site at Lauder (45.0° S, 169.7° E), New Zealand, for 24 December 1998 showed atypically low ozone centered around 24 km altitude (600 K potential temperature). The origin of the anomaly is explained using reverse domain filling (RDF) calculations combined with a PV/O3 fitting technique applied to ozone measurements from the Polar Ozone and Aerosol Measurement (POAM) III instrument. The RDF calculations for two isentropic surfaces, 550 and 600 K, show that ozone-poor air from the Antarctic polar vortex reached New Zealand on 24–26 December 1998. The vortex air on the 550 K isentrope originated in the ozone hole region, unlike the air on 600 K where low ozone values were caused by dynamical effects. High-resolution ozone maps were generated, and their examination shows that a vortex remnant situated above New Zealand was the cause of the altered ozone profile on 24 December. The maps also illustrate mixing of the vortex filaments into southern midlatitudes, whereby the overall mid-latitude ozone levels were decreased.Key words. Atmospheric composition and structure (middle atmosphere composition and chemistry) – Meteorology and atmospheric dynamics (middle atmosphere dynamics)

scholarly journals Nitric acid in the stratosphere based on Odin observations from 2001 to 2009 – Part 1: A global climatology

2009 ◽  
Vol 9 (18) ◽  
pp. 7031-7044 ◽  
Author(s):  
J. Urban ◽  
M. Pommier ◽  
D. P. Murtagh ◽  
M. L. Santee ◽  
Y. J. Orsolini
Keyword(s):  
Nitric Acid ◽  
Potential Temperature ◽  
Polar Vortex ◽  
Data Sets ◽  
High Latitudes ◽  
Vertical Range ◽  
Spatial And Seasonal Variation ◽  
Antarctic Polar Vortex ◽  
Different Characteristics ◽  
The Antarctic

Abstract. The Sub-Millimetre Radiometer (SMR) on board the Odin satellite, launched in February 2001, observes thermal emissions of stratospheric nitric acid (HNO3) originating from the Earth limb in a band centred at 544.6 GHz. Height-resolved measurements of the global distribution of nitric acid in the stratosphere were performed approximately on two observation days per week. An HNO3 climatology based on more than 7 years of observations from August 2001 to April 2009 covering the vertical range between typically ~19 and 45 km (~1.5–60 hPa or ~500–1800 K in terms of potential temperature) was created. The study highlights the spatial and seasonal variation of nitric acid in the stratosphere, characterised by a pronounced seasonal cycle at middle and high latitudes with maxima during late fall and minima during spring, strong denitrification in the lower stratosphere of the Antarctic polar vortex during winter (the irreversible removal of NOy by the sedimentation of cloud particles containing HNO3), as well as large quantities of HNO3 formed every winter at high-latitudes in the middle and upper stratosphere. A strong inter-annual variability is observed in particular at high latitudes. A comparison with a stratospheric HNO3 climatology, based on over 7 years of UARS/MLS (Upper Atmosphere Research Satellite/Microwave Limb Sounder) measurements from the 1990s, shows good consistency and agreement of the main morphological features in the potential temperature range ~465 to ~960 K, if the different characteristics of the data sets such as the better altitude resolution of Odin/SMR as well as the slightly different altitude ranges are considered. Odin/SMR reaches higher up and UARS/MLS lower down in the stratosphere. An overview from 1991 to 2009 of stratospheric nitric acid is provided (with a short gap between 1998 and 2001), if the global measurements of both experiments are taken together.

scholarly journals Observation of an unusual mid-stratospheric aerosol layer in the Arctic: possible sources and implications for polar vortex dynamics

2003 ◽  
Vol 21 (4) ◽  
pp. 1057-1069 ◽  
Author(s):  
M. Gerding ◽  
G. Baumgarten ◽  
U. Blum ◽  
J. P. Thayer ◽  
K.-H. Fricke ◽  
...  
Keyword(s):  
Middle Atmosphere ◽  
Water Solution ◽  
Polar Vortex ◽  
Atmospheric Temperature ◽  
Stratospheric Aerosol ◽  
Atmospheric Composition ◽  
The Arctic ◽  
Aerosol Layer ◽  
Particle Sedimentation ◽  
Composition And Structure

Abstract. By the beginning of winter 2000/2001, a mysterious stratospheric aerosol layer had been detected by four different Arctic lidar stations. The aerosol layer was observed first on 16 November 2000, at an altitude of about 38 km near Søndre Strømfjord, Greenland (67° N, 51° W) and on 19 November 2000, near Andenes, Norway (69°  N, 16°  E). Subsequently, in early December 2000, the aerosol layer was observed near Kiruna, Sweden (68°  N, 21°  E) and Ny-Ålesund, Spitsbergen (79°  N, 12°  E). No mid-latitude lidar station observed the presence of aerosols in this altitude region. The layer persisted throughout the winter 2000/2001, at least up to 12 February 2001. In November 2000, the backscatter ratio at a wavelength of 532 nm was up to 1.1, with a FWHM of about 2.5 km. By early February 2001, the layer had sedimented from an altitude of 38 km to about 26 km. Measurements at several wavelengths by the ALOMAR and Koldewey lidars indicate the particle size was between 30 and 50 nm. Depolarisation measurements reveal that the particles in the layer are aspherical, hence solid. In the mid-stratosphere, the ambient atmospheric temperature was too high to support in situ formation or existence of cloud particles consisting of ice or an acid-water solution. Furthermore, in the year 2000 there was no volcanic eruption, which could have injected aerosols into the upper stratosphere. Therefore, other origins of the aerosol, such as meteoroid debris, condensed rocket fuel, or aerosols produced under the influence of charged solar particles, will be discussed in the paper. Trajectory calculations illustrate the path of the aerosol cloud within the polar vortex and are used to link the observations at the different lidar sites. From the descent rate of  the layer and particle sedimentation rates, the mean down-ward motion of air within the polar vortex was estimated to be about 124 m/d between 35 and 30 km, with higher values at the edge of the vortex.Key words. Atmospheric composition and structure (aerosols and particles; middle atmosphere composition and chemistry) – meteorology and atmospheric dynamics (middle atmosphere dynamics)

scholarly journals Mixing and Chemical Ozone Loss during and after the Antarctic Polar Vortex Major Warming in September 2002

2005 ◽  
Vol 62 (3) ◽  
pp. 848-859 ◽  
Author(s):  
Paul Konopka ◽  
Jens-Uwe Grooß ◽  
Karl W. Hoppel ◽  
Hildegard-Maria Steinhorst ◽  
Rolf Müller
Keyword(s):  
Potential Temperature ◽  
Polar Vortex ◽  
Vertical Shear ◽  
Lagrangian Model ◽  
Ozone Loss ◽  
Time Period ◽  
The Difference ◽  
Antarctic Polar Vortex ◽  
The Antarctic ◽  
Vortex Split

Abstract The 3D version of the Chemical Lagrangian Model of the Stratosphere (CLAMS) is used to study the transport of CH4 and O3 in the Antarctic stratosphere between 1 September and 30 November 2002, that is, over the time period when unprecedented major stratospheric warming in late September split the polar vortex into two parts. The isentropic and cross-isentropic velocities in CLAMS are derived from ECMWF winds and heating/cooling rates calculated with a radiation module. The irreversible part of transport, that is, mixing, is driven by the local horizontal strain and vertical shear rates with mixing parameters deduced from in situ observations. The CH4 distribution after the vortex split shows a completely different behavior above and below 600 K. Above this potential temperature level, until the beginning of November, a significant part of vortex air is transported into the midlatitudes up to 40°S. The lifetime of the vortex remnants formed after the vortex split decreases with the altitude with values of about 3 and 6 weeks at 900 and 700 K, respectively. Despite this enormous dynamical disturbance of the vortex, the intact part between 400 and 600 K that “survived” the major warming was strongly isolated from the extravortex air until the end of November. According to CLAMS simulations, the air masses within this part of the vortex did not experience any significant dilution with the midlatitude air. By transporting ozone in CLAMS as a passive tracer, the chemical ozone loss was estimated from the difference between the observed [Polar Ozone and Aerosol Measurement III (POAM III) and Halogen Occultation Experiment (HALOE)] and simulated ozone profiles. Starting from 1 September, up to 2.0 ppmv O3 around 480 K and about 70 Dobson units between 450 and 550 K were destroyed until the vortex was split. After the major warming, no additional ozone loss can be derived, but in the intact vortex part between 450 and 550 K, the accumulated ozone loss was “frozen in” until the end of November.

scholarly journals Stratospheric background aerosol and polar cloud observations by laser backscattersonde within the framework of the European project "Stratospheric Regular Sounding"

1999 ◽  
Vol 17 (10) ◽  
pp. 1352-1360 ◽  
Author(s):  
A. Adriani ◽  
F. Cairo ◽  
L. Pulvirenti ◽  
F. Cardillo ◽  
M. Viterbini ◽  
...  
Keyword(s):  
Lower Stratosphere ◽  
Middle Atmosphere ◽  
Polar Vortex ◽  
Atmospheric Composition ◽  
The Arctic ◽  
Tropical Regions ◽  
Convective Systems ◽  
Composition And Structure ◽  
Different Seasons ◽  
Stratospheric Clouds

Abstract. The Stratospheric Regular Sounding project was planned to measure regularly the vertical profiles of several tracers like ozone, water vapor, NOx, ClOx and BrOx radicals, aerosol, pressure and temperature, at three latitudes, to discriminate between the transport and photochemical terms which control their distribution. As part of this project, the "Istituto di Fisica dell'Atmosfera" launched nine laser backscattersondes (LABS) on board stratospheric balloons to make observations of background aerosol and PSCs. LABS was launched with an optical particle counter operated by the University of Wyoming. Observations have been performed in the arctic, mid-latitudes and tropical regions in different seasons. Polar stratospheric clouds have been observed in areas inside and outside the polar vortex edge. A background aerosol was observed both in mid-latitudes and in arctic regions with a backscattering ratio of 1.2 at 692 nm. Very stratified aerosol layers, possibly transported into the lower stratosphere by deep convective systems, have been observed in the lower stratosphere between 20 and 29 km in the tropics in the Southern Hemisphere. Key words. Atmospheric composition and structure (aerosols and particles; middle atmosphere – composition and chemistry; instruments and techniques)

Longitudinally Dependent Ozone Increase in the Antarctic Polar Vortex Revealed by Balloon and Satellite Observations

2009 ◽  
Vol 66 (6) ◽  
pp. 1807-1820 ◽  
Author(s):  
K. Sato ◽  
Y. Tomikawa ◽  
G. Hashida ◽  
T. Yamanouchi ◽  
H. Nakajima ◽  
...  
Keyword(s):  
Potential Temperature ◽  
Polar Vortex ◽  
Mixing Ratio ◽  
Vertical Movements ◽  
Horizontal Structure ◽  
Vertical Coordinate ◽  
Zonal Wavenumber ◽  
Lateral Mixing ◽  
Antarctic Polar Vortex ◽  
The Antarctic

Abstract The horizontal structure of processes causing increases in ozone in the Antarctic polar vortex was examined using data measured in 2003 from an ozonesonde observation campaign at Syowa Station (39.6°E, 69.0°S) and from the Improved Limb Atmospheric Spectrometer II (ILAS-II) onboard the Advanced Earth Observing Satellite II. The ILAS-II data are daily and distributed uniformly at 14 points in the zonal direction, mostly at polar latitudes. The Antarctic ozone hole that developed in 2003 was one of the largest recorded. The period of focus in this study is 26 September through 24 October, when a strong polar vortex was situated in the stratosphere. An ozone mixing ratio contour (1.0 ppmv) moved downward near a height of 20 km during the period of focus. This increase in ozone is likely to result from downward transport of ozone-rich air originating from lower latitudes by Brewer–Dobson circulation. First, the descent rate of the mixing ratio contour was estimated by taking the geometric height as the vertical coordinate for the deep vortex interior around 20 km. A significant longitudinal dependence was observed. An analysis using ECMWF operational data shows that this dependence can be approximately explained by longitudinally dependent vertical movements of the isentropes caused by a zonal wavenumber-1 quasi-stationary planetary wave with amplitude and phases varying on a seasonal time scale. Next, the descent rate was calculated around 500 K (around 20 km) by taking the potential temperature (isentrope) as the vertical coordinate. The longitudinal dependence was still present using this coordinate, meaning that the ozone mixing ratio and its increase are not constant on the isentropic layer even in the interior of the polar vortex. A backward trajectory analysis showed that air parcels with large ozone mixing ratios were mostly transported from the polar vortex boundary region. This result suggests that lateral transport/mixing is important even before the breakup of the polar vortex. Results from a tracer–tracer correlation analysis of O3 and long-lived constituent N2O were also consistent with this inference. The contribution of lateral mixing to the increase in ozone was estimated at about 17% ± 4% that of the Brewer–Dobson circulation around 20 km, using the calculated descent rates. The results of this study also imply that Lagrangian downward motions in the vortex interior are not correctly estimated without accounting for lateral mixing, even if the polar vortex is dynamically stable.

scholarly journals Case study of the development of polar stratospheric clouds using bistatic imaging

2003 ◽  
Vol 21 (8) ◽  
pp. 1869-1878
Author(s):  
C.-F. Enell ◽  
U. Brändström ◽  
B. Gustavsson ◽  
S. Kirkwood ◽  
K. Stebel ◽  
...  
Keyword(s):  
Middle Atmosphere ◽  
Polar Vortex ◽  
Three Dimensions ◽  
Atmospheric Composition ◽  
Polar Stratospheric Clouds ◽  
Composition And Structure ◽  
Threshold Temperatures ◽  
Stratospheric Clouds ◽  
Wave Induced

Abstract. The formation of polar stratospheric clouds (PSCs) is closely related to wave activity on different scales since waves propagating into the stratosphere perturb the temperature profile. We present here a case study of the development of visible PSCs (mother-of-pearl clouds), appearing at the polar vortex edge on 9 January 1997, under-taken by means of ground-based cameras. It is shown that the presence of stratospheric clouds may be detected semi-automatically and that short-term dynamics such as altitude variations can be tracked in three dimensions. The PSC field showed distinct features separated by approximately 20 km, which implies wave-induced temperature variations on that scale. The wave-induced characteristics were further emphasised by the fact that the PSCs moved within a sloping spatial surface. The appearance of visible mother-of-pearl clouds seems to be related to leewave-induced cooling of air masses, where the synoptic temperature has been close to (but not necessarily below) the threshold temperatures for PSC condensation.Key words. Atmospheric composition and structure (aerosols and particles) – Meteorology and atmospheric dynamics (middle atmosphere dynamics; instruments and techniques)

Ozone profile measurements within, at the edge of, and outside the Antarctic polar vortex in the spring of 1988

1990 ◽  
Vol 95 (D7) ◽  
pp. 10023-10035 ◽  
Author(s):  
T. Deshler ◽  
D. J. Hofmann ◽  
J. V. Hereford
Keyword(s):  
Polar Vortex ◽  
Ozone Profile ◽  
Antarctic Polar Vortex ◽  
The Antarctic

scholarly journals Nitric acid in the stratosphere based on Odin observations from 2001 to 2007 – Part 1: A global climatology

2008 ◽  
Vol 8 (3) ◽  
pp. 9569-9590 ◽  
Author(s):  
J. Urban ◽  
M. Pommier ◽  
D. P. Murtagh ◽  
M. L. Santee ◽  
Y. J. Orsolini
Keyword(s):  
Nitric Acid ◽  
Potential Temperature ◽  
Polar Vortex ◽  
Data Sets ◽  
High Latitudes ◽  
Thermal Emissions ◽  
Spatial And Seasonal Variation ◽  
Antarctic Polar Vortex ◽  
Different Characteristics ◽  
The Antarctic

Abstract. The Sub-Millimetre Radiometer (SMR) on board the Odin satellite, launched in February 2001, observes thermal emissions of stratospheric nitric acid (HNO3) originating from the Earth limb in a band centred at 544.6 GHz. Height-resolved measurements of the global distribution of nitric acid in the stratosphere between ~18–45 km (~1.5–60 hPa) were performed approximately on two observation days per week. An HNO3 climatology based on roughly 6 years of observations from August 2001 to December 2007 was created. The study highlights the spatial and seasonal variation of nitric acid in the stratosphere, characterised by a pronounced seasonal cycle at middle and high latitudes with maxima during late fall and minima during spring, strong denitrification in the lower stratosphere of the Antarctic polar vortex during winter (the irreversible removal of NOy by the sedimentation of cloud particles containing HNO3), as well as high quantities of HNO3 formed every winter at high-latitudes in the middle and upper stratosphere. A strong inter-annual variability is observed in particular at high latitudes. A comparison with a stratospheric HNO3 climatology based on UARS/MLS measurements from the 1990s shows a good consistency and agreement of the main morphological features in the potential temperature range ~465 to ~960 K, if the different characteristics of the data sets such as altitude range and resolution are considered.

scholarly journals Energetic particle induced intra-seasonal variability of ozone inside the Antarctic polar vortex observed in satellite data

2015 ◽  
Vol 15 (6) ◽  
pp. 3327-3338 ◽  
Author(s):  
T. Fytterer ◽  
M. G. Mlynczak ◽  
H. Nieder ◽  
K. Pérot ◽  
M. Sinnhuber ◽  
...  
Keyword(s):  
Geomagnetic Activity ◽  
Seasonal Variability ◽  
Transport Model ◽  
Three Dimensional ◽  
Polar Vortex ◽  
Quiet Time ◽  
Significance Level ◽  
Antarctic Polar Vortex ◽  
Ap Index ◽  
The Antarctic

Abstract. Measurements from 2002 to 2011 by three independent satellite instruments, namely MIPAS, SABER, and SMR on board the ENVISAT, TIMED, and Odin satellites are used to investigate the intra-seasonal variability of stratospheric and mesospheric O3 volume mixing ratio (vmr) inside the Antarctic polar vortex due to solar and geomagnetic activity. In this study, we individually analysed the relative O3 vmr variations between maximum and minimum conditions of a number of solar and geomagnetic indices (F10.7 cm solar radio flux, Ap index, ≥ 2 MeV electron flux). The indices are 26-day averages centred at 1 April, 1 May, and 1 June while O3 is based on 26-day running means from 1 April to 1 November at altitudes from 20 to 70 km. During solar quiet time from 2005 to 2010, the composite of all three instruments reveals an apparent negative O3 signal associated to the geomagnetic activity (Ap index) around 1 April, on average reaching amplitudes between −5 and −10% of the respective O3 background. The O3 response exceeds the significance level of 95% and propagates downwards throughout the polar winter from the stratopause down to ~ 25 km. These observed results are in good qualitative agreement with the O3 vmr pattern simulated with a three-dimensional chemistry-transport model, which includes particle impact ionisation.

scholarly journals Rarefied gas flows through meshes and implications for atmospheric measurements

2001 ◽  
Vol 19 (5) ◽  
pp. 563-569 ◽  
Author(s):  
J. Gumbel
Keyword(s):  
Middle Atmosphere ◽  
Rarefied Gas ◽  
Direct Simulation Monte Carlo ◽  
Atmospheric Composition ◽  
Gas Flows ◽  
Atmospheric Measurements ◽  
Rarefied Gas Flows ◽  
Flow Disturbances ◽  
Composition And Structure ◽  
Compression Effects

Abstract. Meshes are commonly used as part of instruments for in situ atmospheric measurements. This study analyses the aerodynamic effect of meshes by means of wind tunnel experiments and numerical simulations. Based on the Direct Simulation Monte Carlo method, a simple mesh parameterisation is described and applied to a number of representative flow conditions. For open meshes freely exposed to the flow, substantial compression effects are found both upstream and downstream of the mesh. Meshes attached to close instrument structures, on the other hand, cause only minor flow disturbances. In an accompanying paper, the approach developed here is applied to the quantitative analysis of rocket-borne density measurements in the middle atmosphere.Key words. Atmospheric composition and structure (instruments and techniques; middle atmosphere – composition and chemistry)

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