Two‐day wave structure and mean flow interactions observed by radar and High Resolution Doppler Imager
David C. Fritts,Joseph R. Isler,Ruth S. Lieberman,M. D. Burrage,Daniel R. Marsh,Takuji Nakamura,Toshitaka Tsuda,Robert A. Vincent,Iain M. Reid +8 more
TLDR
In this paper, the authors examined the structure, wave-mean flow interactions, and potential sources of the 2-day wave in the middle atmosphere during three southern hemisphere summers using four MF and meteor radars at equatorial and subtropical sites and with the High Resolution Doppler Imager (HRDI) instrument aboard the UARS satellite.Abstract:
Data obtained with four MF and meteor radars at equatorial and subtropical sites and with the High Resolution Doppler Imager (HRDI) instrument aboard the UARS satellite were used to examine the structure, wave-mean flow interactions, and potential sources of the 2-day wave in the middle atmosphere during three southern hemisphere summers. The three wave events were highly transient, having typical durations of 20 to 30 days and exhibiting modulation at shorter periods. Temporal variations were found to exhibit good correlations between radar and HRDI data. Radar and HRDI data were used to estimate those components of the Eliassen-Palm flux that could be assessed with these data. Meridional fluxes of momentum and heat were computed using HRDI data and agree reasonably with the momentum fluxes computed from radar data at discrete locations. These fluxes were found to exhibit consistent latitudinal structures each year, suggesting systematic wave excitation and wave-mean flow interactions. Meridional momentum flux gradients were seen to be anticorrelated with zonal wind accelerations in a manner consistent with wave forcing of the large-scale circulation. The apparent wave-mean flow interactions suggest that the 2-day wave could be a transient response to baroclinic instability of the summer hemisphere mesospheric jet. A calculation of the meridional gradient of quasi-geostrophic potential vorticity using HRDI winds and the COSPAR International Reference Atmosphere (CIRA 1986) temperatures exhibits a region of instability in the lower and middle mesosphere extending into subtropical latitudes and provides additional evidence of a possible source of this motion via baroclinic instability of the summer hemisphere jet structure.read more
Citations
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Middle atmosphere effects of the quasi-two-day wave determined from a General Circulation Model
TL;DR: A set of numerical experiments have been conducted using the National Center for Atmospheric Research Thermosphere-Ionosphere-Mesosphere-Electrodynamics General Circulation Model (NCAR Time-GCM) to understand the effects of the quasi-two-day wave (QTDW) on the middle atmosphere horizontal wind and temperature fields as mentioned in this paper.
Journal ArticleDOI
Short‐term variability in the migrating diurnal tide caused by interactions with the quasi 2 day wave
TL;DR: In this paper, the authors used the NCAR Thermosphere ionosphere mesosphere electrodynamics general circulation model (TIME-GCM) to simulate a quasi 2-day wave (QTDW) event under late-January conditions.
Journal ArticleDOI
Large‐scale dynamics of the mesosphere and lower thermosphere: An analysis using the extended Canadian Middle Atmosphere Model
Charles McLandress,William E. Ward,V. I. Fomichev,K. Semeniuk,S. R. Beagley,Norman A. McFarlane,Theodore G. Shepherd +6 more
TL;DR: In this paper, the extended Canadian Middle Atmosphere Model is used to investigate the large-scale dynamics of the mesosphere and lower thermosphere (MLT), and it is shown that the 4-day wave is substantially amplified in southern polar winter in the presence of instabilities arising from strong vertical shears in the MLT zonal mean zonal winds brought about by parameterized nonorographic gravity wave drag.
Journal ArticleDOI
The 16-day planetary waves: multi-MF radar observations from the arctic to equator and comparisons with the HRDI measurements and the GSWM modelling results
Yi Luo,Yi Luo,Yi Luo,A. H. Manson,Chris Meek,Christian K. Meyer,M. D. Burrage,D. C. Fritts,Chris Hall,Wayne K. Hocking,John MacDougall,Dennis M. Riggin,Robert A. Vincent +12 more
TL;DR: In this paper, the mesospheric and lower thermospheric (MLT) winds (60-100 km) obtained by multiple MF radars, located from the arctic to the equator at Tromso (70° N, 19° E), Saskatoon (52° n, 107° W), London (43° N and 81° W, Hawaii (21°N, 157° W) and Christmas Island (2°N and 157°W), respectively, are used to study the planetary-scale 16-day waves.
Journal ArticleDOI
Role of gravity waves in the forcing of quasi two-day waves in the mesosphere: An observational study
TL;DR: In this article, a global climatology of quasi-two-day wave (QTDW) amplitudes is derived from 10 years of SABER data, covering the mesosphere and lower thermosphere.
References
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Baroclinic Instability of the Summer Mesosphere: A Mechanism for the Quasi-Two-Day Wave?
TL;DR: In this article, the authors reviewed observations of the quasi-two-day wave and concluded that the weight of evidence indicates that the wave is a solstical phenomenon, with maximum amplitudes in low latitudes of the summer mesosphere.
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