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 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 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.

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 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 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 A quasi-Lagrangian coordinate system based on high resolution tracer observations: implementation for the Antarctic polar vortex

2008 ◽  
Vol 8 (4) ◽  
pp. 16123-16173 ◽  
Author(s):  
E. V. Ivanova ◽  
C. M. Volk ◽  
O. Riediger ◽  
H. Klein ◽  
N. M. Sitnikov ◽  
...  
Keyword(s):  
High Resolution ◽  
Coordinate System ◽  
Vortex Core ◽  
Polar Vortex ◽  
Mixing Ratio ◽  
Lagrangian Coordinate ◽  
Antarctic Polar Vortex ◽  
The Antarctic ◽  
Lagrangian Coordinate System

Abstract. In order to quantitatively analyse the chemical and dynamical evolution of the polar vortex it has proven extremely useful to work with coordinate systems that follow the vortex flow. We propose here a two-dimensional quasi-Lagrangian coordinate system {χi, Δχi}, based on the mixing ratio of a long-lived stratospheric trace gas i, and its systematic use with i = N2O, in order to describe the structure of a well-developed Antarctic polar vortex. In the coordinate system {χi, Δχi} the mixing ratio χi is the vertical coordinate and Δχi = χi(Θ)−χivort(Θ) is the meridional coordinate (χivort(Θ) being a vertical reference profile in the vortex core). The quasi-Lagrangian coordinates {χi, Δχi} persist for much longer time than standard isentropic coordinates, potential temperature Θ and equivalent latitude φe, do not require explicit reference to geographic space, and can be derived directly from high-resolution in situ measurements. They are therefore well-suited for studying the evolution of the Antarctic polar vortex throughout the polar winter with respect to the relevant chemical and microphysical processes. By using the introduced coordinate system {χN2O, ΔχN2O} we analyze the well-developed Antarctic vortex investigated during the APE-GAIA (Airborne Polar Experiment – Geophysica Aircraft in Antarctica – 1999) campaign (Carli et al., 2000). A criterion, which uses the local in-situ measurements of χi=χi(Θ) and attributes the inner vortex edge to a rapid change (δ-step) in the meridional profile of the mixing ratio χi, is developed to determine the (Antarctic) inner vortex edge. In turn, we suggest that the outer vortex edge of a well-developed Antarctic vortex can be attributed to the position of a local minimum of the χH2O gradient in the polar vortex area. For a well-developed Antarctic vortex, the ΔχN2O-parametrization of tracer-tracer relationships allows to distinguish the tracer inter-relationships in the vortex core, vortex boundary region and surf zone and to examine their meridional variation throughout these regions. This is illustrated by analyzing the tracer-tracer relationships χi : χN2O obtained from the in-situ data of the APE-GAIA campaign for i = CFC-11, CFC-12, H-1211 and SF6. A number of solitary anomalous points in the CFC-11 : N2O correlation, observed in the Antarctic vortex core, are interpreted in terms of small-scale cross-isentropic dispersion.

scholarly journals EOS Microwave Limb Sounder observations of the Antarctic polar vortex breakup in 2004

2005 ◽  
Vol 32 (12) ◽  
pp. n/a-n/a ◽  
Author(s):  
G. L. Manney ◽  
M. L. Santee ◽  
N. J. Livesey ◽  
L. Froidevaux ◽  
W. G. Read ◽  
...  
Keyword(s):  
Polar Vortex ◽  
Antarctic Polar Vortex ◽  
The Antarctic

The cause of the strengthening of the Antarctic polar vortex during October–November periods

2019 ◽  
Vol 190 ◽  
pp. 1-5 ◽  
Author(s):  
Vladimir V. Zuev ◽  
Ekaterina Savelieva
Keyword(s):  
Polar Vortex ◽  
Antarctic Polar Vortex ◽  
The Antarctic

scholarly journals Ozone Chemistry during the 2002 Antarctic Vortex Split

2005 ◽  
Vol 62 (3) ◽  
pp. 860-870 ◽  
Author(s):  
Jens-Uwe Grooß ◽  
Paul Konopka ◽  
Rolf Müller
Keyword(s):  
Ozone Depletion ◽  
Polar Region ◽  
Polar Vortex ◽  
Dilution Effect ◽  
Lagrangian Model ◽  
Chemical Effect ◽  
Small Scale ◽  
Air Masses ◽  
Antarctic Polar Vortex ◽  
The Antarctic

Abstract In September 2002, the Antarctic polar vortex was disturbed, and it split into two parts caused by an unusually early stratospheric major warming. This study discusses the chemical consequences of this event using the Chemical Lagrangian Model of the Stratosphere (CLaMS). The chemical initialization of the simulation is based on Halogen Occultation Experiment (HALOE) measurements. Because of its Lagrangian nature, CLaMS is well suited for simulating the small-scale filaments that evolve during this period. Filaments of vortex origin in the midlatitudes were observed by HALOE several times in October 2002. The results of the simulation agree well with these HALOE observations. The simulation further indicates a very rapid chlorine deactivation that is triggered by the warming associated with the split of the vortex. Correspondingly, the ozone depletion rates in the polar vortex parts rapidly decrease to zero. Outside the polar vortex, where air masses of midlatitude origin were transported to the polar region, the simulation shows high ozone depletion rates at the 700-K level caused mainly by NOx chemistry. Owing to the major warming in September 2002, ozone-poor air masses were transported into the midlatitudes and caused a decrease of midlatitude ozone by 5%–15%, depending on altitude. Besides this dilution effect, there was no significant additional chemical effect. The net chemical ozone depletion in air masses of vortex origin was low and did not differ significantly from that of midlatitude air, in spite of the different chemical composition of the two types of air masses.

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