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

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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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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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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Surface ultraviolet radiation over east Siberia: seasonal variations

Annales Geophysicae ◽

10.5194/angeo-20-559-2002 ◽

2002 ◽

Vol 20 (4) ◽

pp. 559-564

Author(s):

A. V. Mikhalev ◽

M. A. Chernigovskaya ◽

A. Yu. Shalin ◽

E. S. Kazimirovsky

Keyword(s):

Ultraviolet Radiation ◽

Uv Radiation ◽

Middle Atmosphere ◽

Ground Level ◽

Atmospheric Composition ◽

Time Interval ◽

East Siberia ◽

Solar Ultraviolet Radiation ◽

Composition And Structure ◽

Asymmetric Behaviour

Abstract. The results of spectral measurements of the daily near-noon surface direct solar ultraviolet radiation in the wavelength range of 295–345 nm obtained in Irkutsk (East Siberia) for the time interval of 1998–2000 are presented. For the period under consideration, the seasonal UV radiation variations are analysed that are associated with the total ozone dynamics, the transition of cyclonic and anticyclonic (Siberian anticyclone) periods, the presence of snow cover, and other factors. The analysis reveals an asymmetric behaviour of the seasonal course in ground-level UV radiation around the time of the summer solstice, with seasonal variation dependence on the wavelength. We have determined the irregular variations of surface UV radiation that is typical for the region, with their properties dependent on the season and on the spectral range analysed. The similarity of the above noted features from year to year was revealed.Key words. Atmospheric composition and structure (Transmission and scattering of radiation; instruments and techniques) – Meteorology and atmospheric dynamics (middle atmosphere dynamics)

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Ultrafast Kelvin waves in the MLT airglow and wind, and their interaction with the atmospheric tides

Annales Geophysicae ◽

10.5194/angeo-36-231-2018 ◽

2018 ◽

Vol 36 (1) ◽

pp. 231-241 ◽

Cited By ~ 5

Author(s):

Fabio Egito ◽

Ricardo Arlen Buriti ◽

Amauri Fragoso Medeiros ◽

Hisao Takahashi

Keyword(s):

Middle Atmosphere ◽

Rotational Temperature ◽

Meridional Wind ◽

Equatorial Region ◽

Kelvin Waves ◽

Atmospheric Composition ◽

Atmospheric Tides ◽

Kelvin Wave ◽

Composition And Structure ◽

Integrated Intensities

Abstract. Airglow and wind measurements from the Brazilian equatorial region were used to investigate the presence and the effects of the 3–4-day ultrafast Kelvin waves in the MLT. The airglow integrated intensities of the OI557.7 nm, O2b(0-1) and OH(6-2) emissions, as well as the OH rotational temperature, were measured by a multichannel photometer, and the zonal and meridional wind components between 80 and 100 km were obtained from a meteor radar. Both instruments are installed in the Brazilian equatorial region at São João do Cariri (7.4∘ S, 36.5∘ W). Data from 2005 were used in this study. The 3–4-day oscillations appear intermittently throughout the year in the airglow. They were identified in January, March, July, August and October–November observations. The amplitudes induced by the waves in the airglow range from 26 to 40 % in the OI557.7 nm, 17 to 43 % in the O2b(0-1) and 15 to 20 % in the OH(6-2) emissions. In the OH rotational temperature, the amplitudes were from 4 to 6 K. Common 3–4-day oscillations between airglow and neutral wind compatible with ultrafast Kelvin waves were observed in March, August and October–November. In these cases, the amplitudes in the zonal wind were found to be between 22 and 28 m s−1 and the vertical wavelength ranges from 44 to 62 km. Evidence of the nonlinear interaction between the ultrafast Kelvin wave and diurnal tide was observed. Keywords. Atmospheric composition and structure (airglow and aurora) – meteorology and atmospheric dynamics (middle atmosphere dynamics; waves and tides)

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Statistical interpolation of ozone measurements from satellite data (TOMS, SBUV and SAGE II) using the kriging method

Annales Geophysicae ◽

10.1007/s00585-000-0666-x ◽

2000 ◽

Vol 18 (6) ◽

pp. 666-678 ◽

Cited By ~ 7

Author(s):

B. J. S. Tranchant ◽

A. P. Vincent

Keyword(s):

Satellite Data ◽

Middle Atmosphere ◽

Stratospheric Aerosol ◽

Atmospheric Composition ◽

Data Sets ◽

Global Correlation ◽

Composition And Structure ◽

Data Resolution ◽

High Vertical Resolution ◽

Statistical Interpolation

Abstract. This study demonstrates that ordinary kriging in spherical coordinates using experimental semi-variograms provides highly usable results, especially near the pole in winter and/or where there could be data missing over large areas. In addition, kriging allows display of the spatial variability of daily ozone measurements at different pressure levels. Three satellite data sets were used: Total Ozone Mapping Spectrometer (TOMS) data, Solar Backscattered UltraViolet (SBUV), and the Stratospheric Aerosol and Gas Experiment (SAGE II) ozone profiles. Since SBUV is a nadir-viewing instrument, measurements are only taken along the sun-synchronous polar orbits of the satellite. SAGE II is a limb-viewing solar occultation instrument, and measurements have high vertical resolution but poor daily coverage. TOMS has wider coverage with equidistant distribution of data (resolution 1° × 1.25°) but provides no vertical information. Comparisons of the resulting SBUV-interpolated (column-integrated) ozone field with TOMS data are strongly in agreement, with a global correlation of close to 98%. Comparisons of SBUV-interpolated ozone profiles with daily SAGE II profiles are relatively good, and comparable to those found in the literature. The interpolated ozone layers at different pressure levels are shown.Key words: Atmospheric composition and structure (middle atmosphere - composition and chemistry) - Meteorology and atmospheric dynamics (middle atmosphere dynamics)

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An explanation for some fallstreak clouds

Annales Geophysicae ◽

10.5194/angeo-20-711-2002 ◽

2002 ◽

Vol 20 (5) ◽

pp. 711-715 ◽

Cited By ~ 1

Author(s):

R. M. Worthington

Keyword(s):

Radar Data ◽

Atmospheric Dynamics ◽

Atmospheric Composition ◽

Cloud Physics ◽

Mountain Wave ◽

Mountain Waves ◽

Meteorology And Atmospheric Dynamics ◽

Composition And Structure ◽

Waves And Tides ◽

Stratospheric Clouds

Abstract. Fallstreak cirrus clouds are associated with super-saturated air, together with waves, instabilities and/or turbulence; however, their precise cause is usually uncertain. This paper uses already-published satellite, radiosonde and radar data, reanalysed to study some large fallstreaks which had been previously overlooked. The fallstreaks – up to 60 km long with a parent cloud 20 km wide – are caused by lifting and/or turbulence from a mountain wave, rather than, for example, Kelvin-Helmholtz instabilities. If turbulent breaking of mountain waves affects ice particle formation, this may be relevant for the seeder-feeder effect on orographic rain, and the efficiency of mountain-wave polar stratospheric clouds for ozone depletion.Key words. Meteorology and atmospheric dynamics (turbulence; waves and tides) – Atmospheric composition and structure (cloud physics and chemistry)

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Evidence of transport, sedimentation and coagulation mechanisms in the relaxation of post-volcanic stratospheric aerosols

Annales Geophysicae ◽

10.5194/angeo-19-1157-2001 ◽

2001 ◽

Vol 19 (9) ◽

pp. 1157-1162 ◽

Cited By ~ 7

Author(s):

D. Fussen ◽

F. Vanhellemont ◽

C. Bingen

Keyword(s):

Middle Atmosphere ◽

Aerosol Particles ◽

Atmospheric Composition ◽

Number Density ◽

Distribution Width ◽

Latitude Range ◽

Atmosphere Composition ◽

Composition And Structure ◽

Spatio Temporal ◽

Stratospheric Aerosols

Abstract. Spatio-temporal distributions of stratospheric aerosols, measured by the ORA instrument from August 1992 until May 1993, are presented in the latitude range (40° S–40° N). Particle total number density, mode radius and distribution width are derived and interpreted. The respective roles of advection, sedimentation and coagulation are discussed. We also identify clear transport/sedimentation patterns and we show the enhancement of coagulation in stagnation regions. Efficient transport of aerosol particles up to 50 km is suggested.Key words. Atmospheric composition and structure (aerosols and particles; middle atmosphere-composition and chemistry; volcanic effects)

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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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Use of coupled ozone fields in a 3-D circulation model of the middle atmosphere

Annales Geophysicae ◽

10.1007/s00585-999-0415-8 ◽

1999 ◽

Vol 17 (3) ◽

pp. 415-429 ◽

Cited By ~ 9

Author(s):

T. Reddmann ◽

R. Ruhnke ◽

W. Kouker

Keyword(s):

Middle Atmosphere ◽

Lower Boundary ◽

Coupled Model ◽

Circulation Model ◽

Atmospheric Composition ◽

Heating Rates ◽

Lower Boundary Condition ◽

Detailed Chemistry ◽

Composition And Structure ◽

On Line

Abstract. With a detailed chemistry scheme for the middle atmosphere up to 70 km which has been added to the 3-D Karlsruhe simulation model of the middle atmosphere (KASIMA), the effects of coupling chemistry and dynamics through ozone are studied for the middle atmosphere. An uncoupled version using an ozone climatology for determining heating rates and a coupled version using on-line ozone are compared in a 10-month integration with meteorological analyses for the winter 1992/93 as the lower boundary condition. Both versions simulate the meteorological situation satisfactorily, but exhibit a too cold lower stratosphere. The on-line ozone differs from the climatological data between 20 and 40 km by exhibiting too high ozone values, whereas in the lower mesosphere the ozone values are too low. The coupled model version is stable and differs only above 40 km significantly from the uncoupled version. Direct heating effects are identified to cause most of the differences. The well-known negative correlation between temperature and ozone is reproduced in the model. As a result, the coupled version slightly approaches the climatological ozone field. Further feedback effects are studied by using the on-line ozone field as a basis for an artificial climatology. For non-disturbed ozone conditions realistic monthly and zonally averaged ozone data are sufficient to determine the heating rates for modelling the middle atmosphere.Key words. Atmospheric composition and structure (middle atmosphere · composition and chemistry) · Meteorology and atmospheric dynamics (middle atmosphere dynamics).

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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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