Properties of the quasi 16 day wave derived from EOS MLS obs

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TitleProperties of the quasi 16 day wave derived from EOS MLS observationsAbstractThis paper describes the use of EOS Microwave Limb Sounder (MLS) data to observe the field of traveling planetary waves with quasi 16 day periods. This study utilizes MLS v2.2 temperature and geopotential data between 1 January 2005 and 31 December 2008 in the range 316 hPa to 0.001 hPa (approximately 8 to 97 km) to examine these waves. Analysis demonstrates that the quasi 16 day wavefield is made up of a number of components with westward and eastward propagating s = 1 and s = 2 waves generally dominant. In the Northern Hemisphere the westward and eastward propagating s = 1 waves have similar magnitudes and are larger than the other modes, while in the Southern Hemisphere, the eastward propagating s = 1 and s = 2 waves are larger than the westward propagating wave modes. All of the modes examined display strong seasonal patterns in the temperature amplitude, significant variability in the wave activity from year to year, and the presence of strong pulse-like patterns in the activity. All of the modes also display large median temperature amplitudes poleward of 40 degrees in both hemispheres. Our analysis also demonstrates that the variability in winter from year to year is larger in the Northern Hemisphere than the Southern Hemisphere. Detailed study also suggests that the exclusion of waves from regions of negative refractive index squared likely forms much of the seasonal pattern observed. Thus, regions of strong westward wind speeds effectively exclude vertically propagating waves as expected from theory. The reflection and absorption of waves associated with critical lines is also likely to explain the frequent occurrence of standing wave patterns in the EOS MLS temperature observations. This study highlights the potential of MLS observations for observing waves from the upper troposphere to the lower mesosphere. Copyright 2011 by the American Geophysical Union.

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1st AuthorMcDonald, A. AuthorMcDonald, A.Hibbins, R.Jarvis, M.Year2011JournalJournal of Geophysical Research AtmospheresVolume116Number6DOI10.1029/2010JD014719URLhttps://www.scopus.com/inward/recor.....7265ca770c0220acc0d99cad6PublisherBlackwell Publishing LtdKeywordsPlates (structural components)Refractive indexWave propagationWave transmission, Critical linesGeopotentialsMicrowave limb sounderNegative refractive indexNorthern HemispheresNumber of componentsPlanetary WavesPropagating wave modesPulse-likeQuasi-16-day wavesSeasonal patternsSouthern HemisphereStanding wave patternsStrong seasonal patternTemperature amplitudeTemperature observationsUpper troposphereWave activityWavefieldsWind speed, Upper atmosphere, amplitudedata setEOSgeopotentialmesospheremicrowave limb sounderNorthern Hemisphereplanetary waverefractive indexseasonalitySouthern Hemispheretemperature profiletropospherewave actionwave fieldwave propagationwave reflection

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CitationMcDonald, A., Hibbins, R. and Jarvis, M. (2011). Properties of the quasi 16 day wave derived from EOS MLS observations. Journal of Geophysical Research Atmospheres, 116(6)