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

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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OH(6-2) spectra and rotational temperature measurements at Davis, Antarctica

Annales Geophysicae ◽

10.1007/s00585-997-0077-3 ◽

1998 ◽

Vol 16 (1) ◽

pp. 77-89 ◽

Cited By ~ 37

Author(s):

P. A. Greet ◽

W. J. R. French ◽

G. B. Burns ◽

P. F. B. Williams ◽

R. P. Lowe ◽

...

Keyword(s):

Middle Atmosphere ◽

Transition Probabilities ◽

Rotational Temperature ◽

Diurnal Variations ◽

Atmospheric Composition ◽

Data Set ◽

Average Temperature ◽

Composition And Structure ◽

Seasonal And Diurnal Variations ◽

Significant Contamination

Abstract. The OH(6-2) band was monitored during 1990 at Davis, Antarctica (68.6°S, 78.0°E) using a Czerny-Turner scanning spectrometer. Spectra obtained with a 0.15-nm bandwidth and wavelength steps of 0.005 nm have been recorded in an attempt to isolate auroral features. This has enabled detailed study of weak features in the region λ837.5–855.5 nm. These weak features can contribute to the apparent intensity of P-branch lines and to the background. Their presence is allowed for in our calculation of rotational temperature, but the P1(3) line is excluded because of significant contamination. An average temperature of 221±2 K is obtained from a selected data set of 104 spectra. The mid-winter average temperature, for the months of May, June and July, is 224±2 K, which is consistent with the 1986 CIRA model values for mid-winter at this height and latitude, but this result is dependent on the choice of transition probabilities. Preliminary assessments of seasonal and diurnal variations in rotational temperature and intensity are presented. Key words. Atmospheric composition and structure · Airglow and aurora; Middle-atmosphere composition and chemistry · Pressure · density and temperature

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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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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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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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Meteor radar observations of atmospheric waves in the equatorial mesosphere/lower thermosphere over Ascension Island

Annales Geophysicae ◽

10.5194/angeo-22-387-2004 ◽

2004 ◽

Vol 22 (2) ◽

pp. 387-404 ◽

Cited By ~ 43

Author(s):

D. Pancheva ◽

N. J. Mitchell ◽

P. T. Younger

Keyword(s):

Zonal Wind ◽

Middle Atmosphere ◽

Lower Thermosphere ◽

Meridional Wind ◽

Kelvin Wave ◽

Vertical Wavelength ◽

Period Range ◽

Meridional Component ◽

Ascension Island ◽

Waves And Tides

Abstract. Some preliminary results about the planetary wave characteristics observed during the first seven months (October 2001-April 2002) of observations over Ascension Island (7.9°S, 14.4°W) are reported in this study. The zonal wind is dominated by the 3–7-day waves, while the meridional component – by the quasi-2-day wave. Two wave events in the zonal wind are studied in detail: a 3–4-day wave observed in the end of October/November and the 3–6-day wave in January/February. The moderate 3- and 3.2-day waves are interpreted as an ultra-fast Kelvin wave, while for the strong 4-day wave we are not able to make a firm decision. The 6-day wave is interpreted as a Doppler-shifted 5-day normal mode, due to its very large vertical wavelength (79km). The quasi-2-day wave seems to be present almost continuously in the meridional wind, but the strongest bursts are observed mainly in December and January. The observed period range is large, from 34 to 68h, with some clustering around 43–44 and 50h. The estimated vertical wavelengths indicate shorter lengths during the equinoxes, in the range of 25-30km, and longer ones, ∼40–50km, in January/February, when the 48-h wave is strongest. Key words. Meteorology and atmospheric dynamics middle atmosphere dynamics, waves and tides)

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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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Morphology of the Wavenumber 1 and Wavenumber 2 Stratospheric Kelvin Waves Using the Long-Term Era-Interim Reanalysis Dataset

Atmosphere ◽

10.3390/atmos11040421 ◽

2020 ◽

Vol 11 (4) ◽

pp. 421

Author(s):

Chen-Jeih Pan ◽

Shih-Sian Yang ◽

Uma Das ◽

Wei-Sheng Chen

Keyword(s):

Temporal Variations ◽

Equatorial Region ◽

Kelvin Waves ◽

Full Time ◽

Kelvin Wave ◽

Reanalysis Dataset ◽

Quasi Biennial Oscillation ◽

Cycle Variation ◽

The Waves

The atmospheric Kelvin wave has been widely studied due to its importance in atmospheric dynamics. Since a long-term climatological study is absent in the literature, we have employed the two-dimensional fast Fourier transform (2D-FFT) method for the 40-year long-term reanalysis of the dataset, ERA-Interim, to investigate the properties of Kelvin waves with wavenumbers 1 (E1) and 2 (E2) at 6–24 days wave periods over the equatorial region of ±10° latitude between a 15 and 45 km altitude during the period 1979–2019. The spatio-temporal variations of the E1 and E2 wave amplitudes were compared to the information of stratospheric quasi-biennial oscillation (QBO), and the wave amplitudes were found to have an inter-QBO cycle variation that was related to sea surface temperature and convections, as well as an intra-QBO cycle variation that was caused by interactions between the waves and stratospheric mean flows. Also, the E1 waves with 6–10 day periods and the E2 waves with 6 days period were observed to penetrate the westerly regime of QBO, which has a thickness less than the vertical wavelengths of those waves, and the waves could further propagate upward to higher altitudes. In a case study of the period 2006–2013, the wave amplitudes showed a good correlation with the Niño 3.4 index, outgoing longwave radiation (OLR), and precipitation during 2006–2013, though this was not the case for the full time series. The present paper is the first report on the 40-year climatology of Kelvin waves, and the morphology of Kelvin waves will help us diagnose the anomalies of wave activity and QBO in the future.

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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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