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

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)

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

Annales Geophysicae ◽

10.1007/s00585-999-1352-2 ◽

1999 ◽

Vol 17 (10) ◽

pp. 1352-1360 ◽

Cited By ~ 6

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)

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

Annales Geophysicae ◽

10.5194/angeo-21-1057-2003 ◽

2003 ◽

Vol 21 (4) ◽

pp. 1057-1069 ◽

Cited By ~ 22

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)

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The red-sky enigma over Svalbard in December 2002

Annales Geophysicae ◽

10.5194/angeo-23-1593-2005 ◽

2005 ◽

Vol 23 (5) ◽

pp. 1593-1602

Author(s):

F. Sigernes ◽

N. Lloyd ◽

D. A. Lorentzen ◽

R. Neuber ◽

U.-P. Hoppe ◽

...

Keyword(s):

Scattered Light ◽

Atmospheric Composition ◽

The Sun ◽

Polar Stratospheric Clouds ◽

Atmospheric Sciences ◽

Composition And Structure ◽

History Of Geophysics ◽

History Of ◽

Instruments And Techniques ◽

Stratospheric Clouds

Abstract. On 6 December 2002, during winter darkness, an extraordinary event occurred in the sky, as viewed from Longyearbyen (78° N, 15° E), Svalbard, Norway. At 07:30 UT the southeast sky was surprisingly lit up in a deep red colour. The light increased in intensity and spread out across the sky, and at 10:00 UT the illumination was observed to reach the zenith. The event died out at about 12:30 UT. Spectral measurements from the Auroral Station in Adventdalen confirm that the light was scattered sunlight. Even though the Sun was between 11.8 and 14.6deg below the horizon during the event, the measured intensities of scattered light on the southern horizon from the scanning photometers coincided with the rise and setting of the Sun. Calculations of actual heights, including refraction and atmospheric screening, indicate that the event most likely was scattered solar light from a target below the horizon. This is also confirmed by the OSIRIS instrument on board the Odin satellite. The deduced height profile indicates that the scattering target is located 18–23km up in the stratosphere at a latitude close to 73–75° N, southeast of Longyearbyen. The temperatures in this region were found to be low enough for Polar Stratospheric Clouds (PSC) to be formed. The target was also identified as PSC by the LIDAR systems at the Koldewey Station in Ny-Ålesund (79° N, 12° E). The event was most likely caused by solar illuminated type II Polar Stratospheric Clouds that scattered light towards Svalbard. Two types of scenarios are presented to explain how light is scattered. Keywords. Atmospheric composition and structure (Transmissions and scattering of radiation; Middle atmospherecomposition and chemistry; Instruments and techniques) – History of geophysics (Atmospheric Sciences; The red-sky phenomena)

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Occurrence of polar stratospheric clouds at Kiruna

Annales Geophysicae ◽

10.1007/s00585-999-1457-7 ◽

1999 ◽

Vol 17 (11) ◽

pp. 1457-1462 ◽

Cited By ~ 12

Author(s):

C.-F. Enell ◽

Å. Steen ◽

T. Wagner ◽

U. Frieß ◽

K. Pfeilsticker ◽

...

Keyword(s):

Weather Conditions ◽

Data Availability ◽

Atmospheric Composition ◽

Mountain Range ◽

Polar Stratospheric Clouds ◽

Mesoscale Meteorology ◽

Optical Instruments ◽

Composition And Structure ◽

Stratospheric Clouds ◽

Frequent Presence

Abstract. Polar stratospheric clouds (PSCs) are often observed in the Kiruna region in northern Sweden, east of the Scandinavian mountain range, during wintertime. PSC occurrence can be detected by ground-based optical instruments. Most of these require clear tropospheric weather. By applying the zenith-sky colour index technique, which works under most weather conditions, the data availability can be extended. The observations suggest that PSC events, especially of type II (water PSCs) may indeed more common than predicted by synoptic models, which is expected because of the frequent presence of mountain-induced leewaves. However, it will be of importance to increase the density of independent observations.Key words. Atmospheric composition and structure (aerosols and particles · cloud physics and chemistry) · Meteorology and atmospheric dynamics (mesoscale meteorology)

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Antarctic air over New Zealand following vortex breakdown in 1998

Annales Geophysicae ◽

10.5194/angeo-21-2175-2003 ◽

2003 ◽

Vol 21 (11) ◽

pp. 2175-2183 ◽

Cited By ~ 9

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)

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10 years of Polar Stratospheric Clouds lidar measurements at the French antarctic station Dumont d’Urville

10.5194/egusphere-egu21-12508 ◽

2021 ◽

Author(s):

Julien Jumelet ◽

Florent Tencé ◽

Alain Sarkissian ◽

Slimane Bekki ◽

Philippe Keckhut

Keyword(s):

Stratospheric Ozone ◽

Polar Vortex ◽

Atmospheric Composition ◽

Primary Role ◽

Atmospheric Conditions ◽

Polar Stratospheric Clouds ◽

Yearly Average ◽

Lidar Measurements ◽

Spaceborne Monitoring ◽

Stratospheric Clouds

Polar Stratospheric Clouds (PSCs) play a primary role in polar stratospheric ozone depletion processes. Aside from recent improvements in both spaceborne monitoring as well as investigations on microphysics and modeling, there are still caveats on building a comprehensive picture of the PSC particle population, especially considering the fine optical signatures of some particles. In that regard, groundbased instruments provide fine and long term reference measurements that complement the global spaceborne coverage.Operated at the French antarctic station Dumont d&#8217;Urville (DDU) in the frame of the international Network for the Detection of Atmospheric Composition Change (NDACC), the Rayleigh/Mie/Raman lidar provides over the years a solid dataset to feed both process and classification studies, by monitoring cloud and aerosol occurrences in the upper troposphere and lower stratosphere. Located on antarctic shore (66&#176;S - 140&#176;E), the station has a privileged access to polar vortex dynamics. Measurements are weather-dependent with a yearly average of 130 nights of monitoring. Expected PSC formation temperatures are used to evaluate the whole PSC season occurrence statistics.We hereby present a consolidated dataset from 10 years of lidar measurements using the 532nm backscatter ratio, the aerosol depolarisation and local atmospheric conditions to help in building an aerosol/cloud classification. Overall, the DDU PSC pattern is very consistent with expected typical temperature controlled thresholds. Supercooled Ternary Solution (STS) particles are the most observed particle type, closely followed by Nitric Acid Trihydrate (NAT). ICE clouds are more rarely observed. The measurements also feature significant and detailed signatures of various aerosols events having reached the polar antarctic stratosphere, like the Calbuco eruption (2015) or the 2 australian wildfires episodes (2009 and 2019). We aim at refining the identification of those aerosols to include their impact in the scope of the scientific questions studied at DDU.

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Case study of mesospheric front dissipation observed over the northeast of Brazil

Annales Geophysicae ◽

10.5194/angeo-36-311-2018 ◽

2018 ◽

Vol 36 (2) ◽

pp. 311-319 ◽

Cited By ~ 3

Author(s):

Amauri Fragoso Medeiros ◽

Igo Paulino ◽

Cristiano Max Wrasse ◽

Joaquim Fechine ◽

Hisao Takahashi ◽

...

Keyword(s):

Middle Atmosphere ◽

Vertical Wind Shear ◽

The Other ◽

Atmospheric Composition ◽

Meteor Radar ◽

Composition And Structure ◽

Waves And Tides ◽

Wind Profiles ◽

The One

Abstract. On 3 October 2005 a mesospheric front was observed over São João do Cariri (7.4∘ S, 36.5∘ W). This front propagated to the northeast and appeared in the airglow images on the west side of the observatory. By about 1.5 h later, it dissipated completely when the front crossed the local zenith. Ahead of the front, several ripple structures appeared during the dissipative process of the front. Using coincident temperature profile from the TIMED/SABER satellite and wind profiles from a meteor radar at São João do Cariri, the background of the atmosphere was investigated in detail. On the one hand, it was noted that a strong vertical wind shear in the propagation direction of the front produced by a semidiunal thermal tide was mainly responsible for the formation of duct (Doppler duct), in which the front propagated up to the zenith of the images. On the other hand, the evolution of the Richardson number as well as the appearance of ripples ahead of the main front suggested that a presence of instability in the airglow layer that did not allow the propagation of the front to the other side of the local zenith. Keywords. Atmospheric composition and structure (airglow and aurora) – meteorology and atmospheric dynamics (middle atmosphere dynamics; waves and tides)

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Record springtime stratospheric ozone depletion at 80°N in 2020

10.5194/egusphere-egu21-8892 ◽

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

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&#176;N, 86.42&#176;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 NO2 during spring, as well as enhanced reactive halogen species (OClO and BrO). Complementary measurements of HCl and ClONO2 (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 HNO3 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.

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Rarefied gas flows through meshes and implications for atmospheric measurements

Annales Geophysicae ◽

10.5194/angeo-19-563-2001 ◽

2001 ◽

Vol 19 (5) ◽

pp. 563-569 ◽

Cited By ~ 6

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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Mesospheric front observations by the OH airglow imager carried out at Ferraz Station on King George Island, Antarctic Peninsula, in 2011

Annales Geophysicae ◽

10.5194/angeo-36-253-2018 ◽

2018 ◽

Vol 36 (1) ◽

pp. 253-264 ◽

Cited By ~ 5

Author(s):

Gabriel Augusto Giongo ◽

José Valentin Bageston ◽

Paulo Prado Batista ◽

Cristiano Max Wrasse ◽

Gabriela Dornelles Bittencourt ◽

...

Keyword(s):

Antarctic Peninsula ◽

Near Infrared ◽

Middle Atmosphere ◽

Convective Cloud ◽

Atmospheric Composition ◽

Secondary Wave ◽

King George Island ◽

Composition And Structure ◽

Waves And Tides ◽

Energy And Momentum

Abstract. The main goals of this work are to characterize and investigate the potential wave sources of four mesospheric fronts identified in the hydroxyl near-infrared (OH-NIR) airglow images, obtained with an all-sky airglow imager installed at Comandante Ferraz Antarctic Station (EACF, as per its Portuguese acronym) located on King George Island in the Antarctic Peninsula. We identified and analyzed four mesospheric fronts in 2011 over King George Island. In addition, we investigate the atmospheric background environment between 80 and 100 km altitude and discuss the ducts and propagation conditions for these waves. For that, we used wind data obtained from a meteor radar operated at EACF and temperature data obtained from the TIMED/SABER satellite. The vertical wavenumber squared, m2, was calculated for each of the four waves. Even though no clearly defined duct (indicated by positive values of m2 sandwiched between layers above and below with m2 < 0) was found in any of the events, favorable propagation conditions for horizontal propagation of the fronts were found in three cases. In the fourth case, the wave front did not find any duct support and it appeared to dissipate near the zenith, transferring energy and momentum to the medium and, consequently, accelerating the wind in the wave propagation direction (near to south) above the OH peak (88–92 km). The likely wave sources for these four cases were investigated by using meteorological satellite images and in two cases we could find that strong instabilities were potential sources, i.e., a cyclonic activity and a large convective cloud cell. In the other two cases it was not possible to associate troposphere sources as potential candidates for the generation of such wave fronts observed in the mesosphere and secondary wave sources were attributed to these cases. Keywords. Atmospheric composition and structure (airglow and aurora) – meteorology and atmospheric dynamics (middle atmosphere dynamics; waves and tides)

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