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Atmospheric wave - Wikipedia, the free encyclopedia An atmospheric wave is a periodic disturbance in the fields of atmospheric variables (like surface pressure or geopotential height, temperature, or wind velocity) which may either propagate (traveling wave) or not (stationary wave). This wave forcing of the flow is particularly important in the stratosphere, where this momentum deposition by gravity waves gives rise to sudden stratospheric warmings and the quasi-biennial oscillation. In the mathematical description of atmospheric waves, the spherical eigenfunctions are used. en.wikipedia.org /wiki/Atmospheric_wave   (352 words)

Atmospheric Gravity Waves   (Site not responding. Last check: 2007-11-02) Gravity waves are the oscillations of air parcels by the lifting force of bouyancy and the restoring force of gravity. Gravity waves are caused by a variety of sources, including the passage of wind across terrestrial landforms, interaction at the velocity shear of the polar jet stream and radiation incident from space. The airglow emits spectra from chemiluminescence of atmospheric molecules. sprg.ssl.berkeley.edu /atmos/gj_science.html   (410 words)

[No title] The gravity wave theory for upper atmospheric motions initially aroused considerable controversy, particularly among some meteorologists who simply refused to believe that gravity waves (other than topographic waves) could play a significant role in the atmosphere, or who were confused by the counter-intuitive alignment of group and phase velocities of gravity waves (see Hines, 1989). The possible role of gravity waves in the extratropical zonal mean circulation was raised by Hines (1972) who used some observed case studies of waves near the mesopause to estimate that the associated Reynolds stress divergence could (at least on occasion) be of the order of several hundred m-s-1-day-1. Lindzen, R.S., 1971: Equatorial planetary waves in shear I. Atmos. www.soest.hawaii.edu /~kph/HIST.paper.html   (8070 words)

Atmospheric Waves   (Site not responding. Last check: 2007-11-02) Waves in the atmosphere are oscillatory motions that result from a balance between the inertia of the atmosphere and a restoring force. Atmospheric waves are important bacause they can transmit energy and momentum without material transport of air parcels. In buoyancy waves the vertical stability of the atmosphere acts as a restoring force; in inertia-gravity waves the Coriolis force and buoyancy force both act as restoring forces; and in Rossby waves a fluid analogue of spin angular momentum (potential vorticity) acts as the restoring force. www.nws.noaa.gov /om/csd/pds/pcu2/IC2.1/Climo/Awaves.html   (229 words)

Atmospheric Gravity Waves   (Site not responding. Last check: 2007-11-02) It is strongly believed that the periodic disturbances in the power returns reflected from the Earth's surface are the result of modulations by the influence of atmospheric gravity waves (AGWs) on the electron density distribution through which the radar waves propagate. Waves with a period of between 30-40 minutes are seen to propagate in time. The cause of the disturbances was almost certainly atmospheric in nature as the geomagnetic data from this time indicated very little activity. ion.le.ac.uk /atmos_sci/gravwaves.html   (203 words)

NRL - Parabolic Equations for Atmospheric Waves The AG wave contains a large amount of energy near the ground due to a contribution of the Lamb wave; dynamic range of the plots is 50 dB. At infrasonic frequencies close to the buoyancy frequency of the atmosphere, the combined effects of gravity and medium compressibility lead to hybrid AG waves that are significantly different from pure gravity or acoustic waves. The main difference in this case is due to a surface wave that decays exponentially with altitude (a Lamb wave) in the AG wavenumber spectrum that is not present in the gravity wavenumber spectrum. www.nrl.navy.mil /content.php?P=02REVIEW85-2   (266 words)

Mountain Waves Print Version   (Site not responding. Last check: 2007-11-02) As a forecaster, your task is to anticipate mountain wave development, assess its strength, and determine the possibility of clear air turbulence aloft and strong winds, wind shear, and turbulence near the surface. The frequency of an orographic wave is determined by the static stability of the atmosphere. The amplitude of an orographic wave is highly dependent on the structure of the atmosphere, the nature of the airflow, and the size and shape of the mountain. meted.ucar.edu /mesoprim/mtnwave/print.htm   (10474 words)

Atmospheric "Waves" Reduced Ozone Hole If the waves are more frequent and stronger as they move from the surface to the upper atmosphere, they warm the upper air. The waves affect the atmospheric circulation in the Antarctic by strengthening it and warming temperatures, or weakening it and cooling temperatures. A greater number of large "planetary sized waves" in the atmosphere that move from the lower atmosphere into the upper atmosphere were responsible for the smaller Antarctic ozone hole this fall, according to NASA researchers. www.scienceagogo.com /news/20021111212118data_trunc_sys.shtml   (1385 words)

HLA Compliant Total Atmospheric Simulations   (Site not responding. Last check: 2007-11-02) WAVES is part of a tri-services effort that provides an atmospheric simulation from MODTRAN calculations for large scale extinction, CSSM calculations for natural cloud effects, BLIRB calculations for radiative transfer, and ATMOS calculations for blurring due to turbulence. WAVES was conceived and developed under a series of Tri-Service Programs to develop complete modeling and simulation of visualization and imaging of the atmospheric environment. WAVES research initiatives in the past have included development of the n-stream model (improvement over the original 2-stream model), albedo effects, flares, enhanced aerosols choices, and the evaluation of the multiple scattering routine. www.dtc.army.mil /hpcw/1998/gill/gill.html   (3429 words)

Atmospheric waves generated by an eclipse   (Site not responding. Last check: 2007-11-02) These waves will show up in the movement of the ionosphere, as it is blown up and down the field lines by waves in the winds. The atmosphere is washing both southward and eastward with a period of around two and a half hours. As the path of the shadow is curved, the waves on the inside of this curve may be focussed to a point. www.wdc.rl.ac.uk /ionosondes/eclipse/waves.html   (355 words)

Australian Antarctic Division - Atmospheric waves Gravity waves are typically of small scale, having wavelengths of from metres to a few tens of kilometres, and have characteristic periods from minutes to hours. The absorption of these waves and the momentum they carry to high altitudes drives the circulation of the mesosphere out of radiative equilibrium (the temperature of the mesosphere increases from a minimum over the summer pole, which is in continuous sunlight, to a maximum over the winter pole, which is in continuous darkness). Both gravity waves and planetary waves are excited by flow over elevated terrain and by latent heat release in organised convection. www.aad.gov.au /?casid=11568   (330 words)

"Ideological crests versus empirical troughs: John Herschel's and William Radcliffe Birt's research on atmospheric ... He hoped to enlist him for the wave cause believing Sabine could ensure participation of the Royal Navy in making barometric observations on ships and in naval stations (at that time Sabine was the general secretary of the British Association and foreign secretary of the Royal Society with important ties with the Admiralty). He also engaged in the researches of atmospheric electricity: at the Swansea meeting of the Association in 1848 he was requested to undertake the reduction and discussion of the electrical observation made at Kew, and the results formed a report of nearly ninety pages in length which was published in the Association's Report for 1849. In the section devoted to atmospheric waves Birt accordingly eschewed the 'wave-intersection' hypothesis and discussed waves as 'bearing somewhat on storms' to the extent that their troughs were now defined as rectilinear atmospheric streams of the hurricane strength. www.uky.edu /~vjankov/bjhs.html   (5217 words)

Rossby, or atmospheric long waves   (Site not responding. Last check: 2007-11-02) At any one time, there are between 3 and 7 such waves, the number in any particular latitude band dependent upon a fine balance between the speed of the airflow through the trough/ridge system and the wavelength. The wave speed decreases with the square of the wave-length, i.e. The average west-to-east movement of a major long wave is around 2 to 5 degrees of longitude per 24 hr. homepage.ntlworld.com /booty.weather/metinfo/rossby.htm   (717 words)

HST Atmospheric Gravity Waves Observatons   (Site not responding. Last check: 2007-11-02) As a wave passes through a point in the atmosphere, the local pressure will rise and then fall, causing the temperature to cool and then warm very slightly, by about one degree Fahrenheit. One intriguing idea is that the biggest waves will be confined to a narrow altitude range, where the pressure is about 3 to 5 bars, and where there is a layer of gaseous water encircling the planet. These long-distance waves would act as a probe of Jupiter's interior, much like seismic waves on Earth, and would provide information about different atmospheric levels that cannot be observed optically. www2.jpl.nasa.gov /sl9/hst3.html   (338 words)

EO Newsroom: New Images - Atmospheric Gravity Waves over Arabian Sea The wave pattern seen in the image is not from large ocean waves, however. The pattern is the “impression” of atmospheric gravity waves on the surface of the ocean. On its descent into the low-point of the wave (the trough), the air touches the surface of the ocean, roughening the water. earthobservatory.nasa.gov /Newsroom/NewImages/images.php3?img_id=16921   (297 words)

Univeristy of Saskatchewan: Space and Atmospheric Studies Atmospheric waves, whose sources are mainly in the troposphere and ozone-layer, deposit significant energy and momentum in this region, where they also create turbulence. The waves include gravity, tidal and planetary waves; and their daily, seasonal and solar-cycle variations are studied. The planetary atmospheres group was formed in 1991 and has a number of exciting projects in progress in spite of its relative youth. physics.usask.ca /research/isas.htm   (2382 words)

Imaging Studies of Atmospheric Gravity Waves   (Site not responding. Last check: 2007-11-02) At mesospheric heights (~60-100 km) the atmospheric pressure and density are lower than can be achieved in most vacuum systems yet this tenuous region is home to a wealth of dynamical phenomena. In particular atmospheric gravity waves, generated by thunderstorms, severe weather, and by strong winds blowing over large mountain ranges (such as the Rockies), can propagate upwards from their source regions into the mesosphere in only a few hours. At heights above about 80 km these waves start to break (like ocean waves as they reach the shore) and deposit their energy and momentum which has a dramatic influence on the upper atmospheric circulation and the temperature field. www.physics.isu.edu /colloquium/taylor04.html   (194 words)

Infrared Atmospheric Waves When the night sky is photographed in the infrared portion of the spectrum, luminous wave-like structures appear in the upper atmosphere. The wave crests are about 50 kilometers apart; lengthwise, they stretch up to 1.000 kilometers; altitude, about 85 kilometers. Since these waves are seen only at low angles over the horizon, some geophysicists propose they are the result of a geometric effect produced by viewing a rippled layer of weakly emitting gases in the upper atmosphere. www.science-frontiers.com /sf035/sf035p18.htm   (250 words)

Top Story - A WARM POLAR WINTER WAS EASIER ON ARCTIC OZONE - May 28, 2002 These long waves affect the atmospheric circulation in the Arctic by strengthening it and warming temperatures, or weakening it and cooling temperatures. The stronger waves provided the fuel for the atmospheric circulation to warm the stratosphere in the north polar region. The atmospheric circulation brings ozone from the upper to the lower stratosphere, where temperatures are colder. www.gsfc.nasa.gov /topstory/20020528polarwinter.html   (1035 words)

References on atmospheric gravity waves Hirota I., 1984: Climatology of gravity waves in the middle atmosphere. Holton, J., 1982: The role of gravity wave induced drag and diffusion in the momentum budget of the mesosphere. Weinstock, J., 1990: Satured and unsaturated spectra of gravity waves and scale-dependent diffusion. www.igf.fuw.edu.pl /~andii/prac/Bib_GW.html   (2198 words)

wave, in the earth sciences: Seismic and Atmospheric Waves Seismic waves are generated in the earth by the movements of earthquakes or explosions. Seismic waves from explosions have been used to understand the subsurface structure of the crust and upper mantle and in the exploration for oil and gas deposits. Atmospheric waves are caused by differences in temperature, the www.factmonster.com /ce6/sci/A0861895.html   (106 words)

Atmospheric Science at Dalhousie University The atmospheric science classes are Climate Change (2nd year), Introduction to Atmospheric Science, Atmospheric Physics I (Atmospheric Thermodynamics) and II (Introduction to Aerosol and Cloud Physics), Synoptic Meteorology I and II, Atmospheric Dynamics I and II, Physical Oceanography, Atmospheric Chemistry, and Numerical Modelling of Atmospheres and Oceans. The graduate-level atmospheric science classes are Introduction to Atmospheric Science, Atmospheric Physics I (Atmospheric Thermodynamics) and II (Introduction to Aerosol and Cloud Physics), Synoptic Meteorology I and II, Atmospheric Dynamics I and II, Physical Oceanography, Atmospheric Chemistry, Numerical Modelling of Atmospheres and Oceans, and Cloud Physics (Dynamics). The effects of atmospheric waves are known to be important for large-scale temperatures and chemistry, but a detailed understanding of many wave physical processes does not exist. www.atm.dal.ca   (903 words)

Visible Earth: Atmospheric gravity waves and internal waves off Australia   (Site not responding. Last check: 2007-11-02) Atmospheric gravity waves (also called atmospheric internal waves) occur when a uniform layer of air blows over a large obstacle, like a mountain or island. This wave pattern in the air impresses itself onto sea waves when it touches the surface of the ocean. Internal waves happen much in the same way that atmospheric gravity waves do; the main difference being that the waves occur between layers of water with different densities instead of layers of the atmosphere. visibleearth.nasa.gov /view_rec.php?vev1id=26177   (329 words)

[51.14] Atmospheric Travelling Waves from MGS TES   (Site not responding. Last check: 2007-11-02) Modelling efforts have suggested that baroclinic activity in the southern hemisphere is reduced compared to the northern hemisphere (where all ground-based observations of travelling waves have occurred). We have analyzed the data from MGS TES before the spacecraft entered its mapping orbit, subtracting the atmospheric variations that were systematic with latitude, longitude, time of day and season. However, no coherent waves propagating in longitude and time were conclusively detected for any of the data analyzed. www.aas.org /publications/baas/v32n3/dps2000/412.htm   (318 words)

Planetary Waves Break Ozone Holes Stronger planetary waves in the northern hemisphere warm the Arctic stratosphere and suppress ozone destruction. Greenhouse gases, which trap the heat radiating from Earth's surface in the lowest layer of the atmosphere, reduce the heat that reaches the stratosphere. The number of CFC molecules in the lower atmosphere, for example, peaked in 1994 and have since declined. science.nasa.gov /headlines/y2001/ast11oct_1.htm   (1337 words)

MLS Observations of Atmospheric Gravity Waves Gravity waves (GWs) play important roles in determining atmospheric general circulations and thermal structures [e.g., Lindzen, 1981; Holton, 1982]. For limb-scan observations, the radiances are often truncated by 3-6 measurement points to meet the saturation criteria, which yields a horizontal scale of 50-100km. Over the wave conducting regions, longitudianl variations of wave activity contain valuable information on GW sources [McLandress et at, 2000; Jiang et al., 2002]. mls.jpl.nasa.gov /jonathan   (521 words)

Atmospheric Gravity Waves Thesis involved computing the magnitude and direction of atmospheric gravity waves subject to blocking by horizontal winds, i.e. Data from the wind profiles was then analyzed to determine blocking diagrams, which show the forbidden directions and phase velocities of wave propagation at a given height. The blocking diagrams were then compared with experimental observations of gravity waves in airglow to determine the accuracy of the wind profiles and help explain critical layer theory. www.rsmas.miami.edu /personal/eryan/agw   (263 words)

Sounding Rocket Launches to Study Atmospheric Waves The instruments carried on board the Rohini sounding rockets and the balloons measures the height structures of winds and waves in the atmosphere. These waves are believed to be the major driving forces for the evolution of quasi biennial oscillations in the atmosphere. Extended periods of observations by NMRF and Rayleigh Lidar that is collocated with NMRF at Gadanki near Tirupati are also being undertaken to delineate shorter period gravity waves. www.isro.org /pressrelease/Mar16_2000_1.htm   (242 words)

The Infography about Gravity Waves in the Upper Atmosphere Richmond, A.D. (1978) "Gravity Wave Generation, Propagation and Dissipation in the Thermosphere," Journal of Geophysical Research, 83: 4131. Hunsucker, R.D. (1990) "Atmospheric Gravity Waves and Traveling Ionospheric Disturbances: Thirty Years of Research," Proceedings of the 1990 Ionospheric Effects Symposium (IES): 46, Alexandria, Virginia. Jing, N., and R.D. Hunsucker (1993) "A Theoretical Investigation of Sources of Large and Medium Scale Atmospheric Gravity Waves in the Auroral Oval," Journal of Atmospheric and Terrestrial Physics, 55 (13): 1667. www.infography.com /content/641984756403.html   (465 words)

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