Showing papers on "Atmospheric wave published in 1982"
TL;DR: Space-time spectral analysis has been extensively applied to data generated by GFDL general circulation models to determine the wave characteristics, structure and energetics of transient planetary waves, to verify the model with observations and to clarify their generation mechanisms by means of controlled experiments as mentioned in this paper.
Abstract: Space-time spectral analysis methods and their applications to large-scale atmospheric waves are reviewed. Space-time spectral analysis resolves transient waves into eastward and westward moving components and is mathematically analogous to rotary spectral analysis which resolves twodimensional velocity vectors into clockwise and anticlockwise components. Space-time spectral analysis can also resolve transient waves consisting of multiple wavenumbers into standing and traveling wave packets. Space-time energy spectra are governed by space-time spectral energy equations which consist of linear and nonlinear energy transfer spectra. Space-time spectra can be estimated by either the lag correlation method, direct Fourier transform method or the maximum entropy method depending on the length of the time record. By use of the modified space-Fourier transform these spectra can be estimated correctly from polar-orbiting satellite data which are sampled globally at different hours of the day. Space-time spectral analysis has been extensively applied to data generated by GFDL general circulation models to determine the wave characteristics, structure and energetics of transient planetary waves, to verify the model with observations and to clarify their generation mechanisms by means of controlled experiments.
234 citations
TL;DR: In this article, a new class of upstream wave was reported with relatively high frequencies of about 1 Hz and small amplitudes compared to the more common larger amplitude, low-frequency (0.03 Hz) upstream wave.
Abstract: A new class of upstream wave is reported with relatively high frequencies of about 1 Hz and small amplitudes compared to the more common larger amplitude, low-frequency (0.03 Hz) upstream wave. The waves were first noted in association with beams of ions reflected back upstream at the bowshock, and although beam presence appears to be a necessary condition for the observation of the waves, it is not a sufficient condition for the existence of the waves. Magnetometer measurements are used to determine intrinsic properties of the waves, and simultaneous two point measurements are used to calculate and eliminate Doppler shifting effects. Results indicate that the waves are right-hand elliptically polarized whistler mode waves with plasma rest frame frequencies of about 20-100 times the proton gyrofrequency and wavelengths of about 100 km.
106 citations
TL;DR: In this article, the authors modeled wave-like cloud features on Venus, which at times form a Y-like structure which encircles the planet, were modelled numerically and linearized primitive equations for a shallow, hydrostatic atmosphere were defined, along with upper boundary layer conditions for the 4-6 day periods detected in the atmospheric response to forcing.
Abstract: Observed wave-like cloud features on Venus, which at times form a Y-like structure which encircles the planet, were modelled numerically. Linearized primitive equations for a shallow, hydrostatic atmosphere are defined, along with upper boundary layer conditions for the 4-6 day periods detected in the atmospheric response to forcing. The basic state of the Venus atmosphere was considered to display variations in static stability and the mean zonal wind as a function of altitude. Forcing was introduced over a wide range of frequencies in order to produce the target oscillation modes. Combination of a midlatitude Rossby wave and an equatorial Kelvin wave was found to yield the observed Y-shape, which could be preserved with nonlinear coupling.
41 citations
TL;DR: In this paper, the local dispersion relation for magneto-atmospheric waves is discussed in terms of the linearized theory of waves in a plane-stratified, inviscid, perfectly conducting atmosphere under uniform gravity.
Abstract: The local dispersion relation for magneto-atmospheric waves is discussed in terms of the linearized theory of waves in a plane-stratified, inviscid, perfectly conducting atmosphere under uniform gravity. The normally used local dispersion relation is demonstrated to not be unique, depending instead on the order of derivation from the fundamental first-order perturbation equations of continuity, momentum, energy, and induction. Furthermore, it is shown that the local dispersion relation predicts that the cutoff frequency decreases with increasing magnetic field strength, while the WKB approximation method projects an increase in the cutoff frequency with increasing magnetic field strength. A new form of the local dispersion relation is developed, and consideration is given to the special case of a global dispersion relation in conditions of an isothermal atmosphere with a horizontal magnetic field.
29 citations
15 Nov 1982
23 citations
TL;DR: In this article, evidence is found in Japanese station pressure records for the 11-yr solar cycle term and a long-period signal near 20 yr which is identified as the 186-yr MN lunar nodal term in atmospheric tides Amplitudes of the identified MN term are highly variable with a nominal amplitude of 1 mb and, for the seven available stations, the term is in phase (00±23yr) with the MN term in 30 temperature records in north-eastern North America.
Abstract: Summary Evidence is found in Japanese station pressure records for the 11-yr solar cycle term and a long-period signal near 20 yr which we identify as the 186-yr MN lunar nodal term in atmospheric tides Amplitudes of the identified MN term are highly variable with a nominal amplitude of 01 mb and, for the seven available stations, the term is in phase (00±23yr) with the MN term in 30 temperature records in north-eastern North America These results are important because of my proposal that enhanced drought conditions in the western United States on a time-scale of ˜ 20 yr are neither ‘recurrent’ nor ‘rhythmic’, but rather periodic with a period 186yr And the influence of the Rocky Mountains (as well as the Tibetan Plateau) on standing atmospheric waves vis-a-vis precipitation is the common forcing function for the signal in temperature and drought conditions
19 citations
TL;DR: In this paper, the spectral energy of standing long waves was analyzed using the NMC (National Meteorological Center) data of winter 1976-1977 and it was found that the standing long wave is responsible for the major horizontal sensible heat transport and also for the significant horizontal momentum transport.
Abstract: The contributions of standing (time-mean) and transient (time-departure) waves to the atmospheric spectral energetics are analyzed using the NMC (National Meteorological Center) data of winter 1976-1977. It is found that the standing long waves are responsible for the major horizontal sensible heat transport and also for the significant horizontal momentum transport. Furthermore, the major contents of eddy available energy and eddy kinetic energy of standing waves are in the long-wave regime. However, the spectral energetics analysis indicates that the standing long waves are energetically less efficient than the transient long and short waves. It is suggested that the lower efficiency of the standing long waves in the atmospheric energetics may be one of the physical factors causing the underforecast of the standing long waves in the numerical weather prediction models.
17 citations
TL;DR: In this article, a wave-group propagating upwards can be associated first with a sporadic-E layer whose total electron content varies periodically, and later with a disturbance in the F-region varying with the same period.
14 citations
TL;DR: In this paper, it is suggested that the gravity waves may have been generated by shear flow instability within the frontal layer of the air masses and that some of the observed waves could have been ducted in or near the frontal zone.
12 citations
12 citations
TL;DR: In this paper, the structure of atmospheric turbulence is reviewed in tems of the refractive index structure parameter and the mean and fluctuating refraction effects of the turbulent atmosphere on the propagation of electromagnetic waves are addressed.
Abstract: Telescopic observations to terrestrial and extraterrestrial objects are affected by atmospheric turbulence. The structure of atmospheric turbulence is reviewed in tems of the refractive index structure parameter. The mean and fluctuating refraction effects of the turbulent atmosphere on the propagation of electromagnetic waves are addressed. The known formulae for the variance and the spectrum of the angle-of-arrival fluctuations are presented and experimental results are summarised. The angular resolution is compared with the pointing precision of a telescope for visual observations through a turbulent atmosphere. The ultimate precision of direction measurements is shown to be a function of instrumental design parameters, the strength of atmospheric turbulence, and the length of the averaging period.
TL;DR: In this article, it is suggested that spectral analysis of microwave and infrared emissions, as monitored by a geostationary satellite-borne radiometer, may reveal important characteristics and relationships between temperature profiles and natural oscillations in the earth's atmosphere over a wide height range.
Abstract: Atmospheric microwave emissions from oxygen near 58.0, 54.0, and 51.0 GHz and water vapor at 22.235 GHz are monitored simultaneously at a time interval of 10 s. Power spectral analysis of radiometer output indicated frequent occurrence of enhanced emissions at periods between 3 and 13 min. These are attributed to local buoyancy Brunt-Vaisala oscillations in the earth's atmosphere. Inversion of integrated brightness temperatures makes it possible to remote sense temperature profiles and natural waves simultaneously. It is suggested that spectral analysis of microwave and/or infrared emissions, as monitored by a geostationary satellite-borne radiometer, may reveal important characteristics and relationships between temperature profiles and natural oscillations in the earth's atmosphere over a wide height range.
TL;DR: In this paper, the authors searched their own seismograph records with positive results (Table 1) for the direct air wave (A1) at all three stations (Kiruna, Umea, Uppsala).
Abstract: The famous volcanic eruption of Mount St. Helens on May 18, 1980, generated atmospheric and magnetic waves that encircled the earth. Ritsema [1980] reports atmospheric pressure waves (or gravity waves), recorded by seismographs and barographs, at De Bilt in Holland. Stimulated by his report, I searched our own seismograph records with positive results (Table 1). The instruments used are the Press-Ewing long-period vertical-component seismographs (seismometer period, 15 s; galvanometer period, 90–100 s). Clear records of the direct air wave (A1) were obtained at all three stations (Kiruna, Umea, Uppsala), while the antipodal wave (A2) was recorded less clearly and only at one station (Uppsala). In all cases, the initial motion is down on the records, which corresponds to an upward motion of the pendulum.
TL;DR: The effects of gravity waves on OH and 5577 0I emissions have been used to investigate the possible production of "secondary" waves or "ripples" by a "primary" wave as mentioned in this paper.
TL;DR: In this article, the authors identified atmospheric internal gravity waves that formed over a coastal and an inland site from analog records of wind speed and direction, and found that more waves formed during the spring and summer at the coastal site as compared to other seasons.
Abstract: Atmospheric internal gravity waves that formed over a coastal and an inland site were identified from analog records of wind speed and direction. Internal gravity waves occurred at all hours at the coastal site but only during nights inland. More waves formed during the spring and summer at the coastal site as compared to other seasons. The frequency distribution of internal gravity waves inland showed no preference in seasons.
01 Jan 1982
TL;DR: In this paper, it was shown that the larger the amplitude and width, the faster the waves for the nonlinear inertia waves and the slower the Rossby solitary waves, to which perhaps the polar vortex and the blocking orcut-off systems belong.
Abstract: In this paper, starting with the equations describing the atmospheric motion and by arelatively simple method, we find that, nearby the mechanical equilibrium point, all thefinite amplitude nonlinear inertia waves, internal gravity waves and Rossby waves in thedispersive atmosphere satisfy the KdV (Korteweg-de Vries) equation, its solution being thecnoidal waves and solitary waves. For the finite amplitude Rossby waves, we find the newdispersive relation which is different from the Rossby formula and contains the amplitudeparameter. It is shown that the larger the amplitude and width, the faster are the wavesfor the finite amplitude inertia waves and internal gravity waves, and the slower are thewaves for the Rossby solitary waves, to which perhaps the polar vortex and the blocking orcut-off systems belong. This treatise gives the nonlinear waves a new way and inspires usto study the nonlinear adjustment process and evolution process and the turbulence structure.
TL;DR: In addition to the heating the corona by sound waves, there exists a radiation pressure caused by the absorption of acoustic waves as well as plasma waves as mentioned in this paper, which has to be taken into account.
Abstract: In addition to the heating the corona by sound waves, there exists a radiation pressure caused by the absorption of acoustic waves as well as plasma waves. Whereas in the hydrostatic balance of the solar atmosphere, the light pressure can be neglected, the radiation pressure due to acoustic waves and Alfven waves is much higher and has to be taken into account.
TL;DR: The Venera spacecraft observed that the entire atmosphere moves in the same retrograde (westward) direction at average speeds of up to about 110 m/sec, which may be explained by zonal jets arising from interactions of meridional cells, viscosity and solar heating as discussed by the authors.
Abstract: Observations of and possible explanations for the dynamics of the Venus atmosphere as revelaed by Pioneer Venus and the Venera spacecraft are discussed. An important observation was that the entire atmosphere moves in the same retrograde (westward) direction at average speeds of up to about 110 m/sec, which may be explained by zonal jets arising from interactions of meridional cells, viscosity and solar heating. Atmospheric thermal tides, temperature and wind perturbations caused by solar heating were also observed which may have influences on tidal winds and warming at the poles. In addition, atmospheric waves with periods of 5.3 and 2.9 earth days have been detected between the Venus cloud tops, and calculations of baroclinically unstable waves on Venus have been made with a general circulation model.
01 Jan 1982
01 Jan 1982
TL;DR: In this paper, the authors used wave spectral measurements together with correlation flux measurements in the marine surface layer and showed an unexpected increase in energy in the 6-sec wave band (.15 \rightarrow.17 hz ), which was well correlated with the variation of the neutral atmospheric drag coefficient and the surface roughness.
Abstract: Measurements made on both sides of an atmospheric front of the neutral atmospheric drag coefficient, C_{dn} , and ocean surface wave spectra showed a large variation in C_{dn} at constant wind speed that was unexplained by conventional formulations. In our investigation, which for the first time made wave spectral measurements together with correlation flux measurements in the marine surface layer, coincident wave spectral measurements showed an unexpected increase in energy in the 6-sec wave band ( .15 \rightarrow.17 hz ), which was well correlated with the variation of C_{dn} and the surface roughness, z_{o} . We derived a relation of z_{o} to the wave spectra which reduces to Charnock's relation in situations of dynamic equilibrium between the wind field and the surface waves. In situations of disequilibrium, the relation shows a strong dependence of z_{o} on the 6-sec wave field. This relationship of z_{o} to the surface wave spectra helps explain the apparently high values of C_{dn} behind moving fronts reported in the literature.
01 Jan 1982
TL;DR: A short review of the last years investigations of the fine and large scale structure of the solar atmosphere and connected with this structure atmospheric waves is given in this article, where the intergranular network and the super-granulation are considered as general strong magnetic field and the measured faint magnetic field as a statistical mean of quasi-open fields of granulation.
Abstract: A short review of the last years investigations of the fine and large scale structure of the solar atmosphere and connected with this structure atmospheric waves is given. The intergranular network and the super-granulation are considered as general strong magnetic field and the measured faint magnetic field as a statistical mean of quasiopen fields of granulation. There is a tendency of systematical formation of large scale structures beginning from the mesogranulation to the configurations of 105 km scale size.
TL;DR: In this paper, the excitation of the guided acoustic-gravity waves in the upper thermosphere in response to enhanced auroral electrojets is calculated in the absence of dissipation under a fully ducted condition.