Diurnal propagating tides in the low-latitude middle atmosphere

Forbes, Jeffrey M.; Groves, G. V.

doi:10.1016/0021-9169(87)90050-x

Cited by 46 publications

(26 citation statements)

References 17 publications

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“…These phase profiles are used to estimate the vertical wavelengths, which are found to be ∼25 km. This wavelength is consistent with that of the (1,1) mode of the migrating diurnal tidal component (Forbes and Groves, 1987). Figure 4 shows the altitude profiles of amplitude and phase for meridional diurnal tides for different months.…”

Section: Diurnal Tidessupporting

confidence: 81%

Vertical propagation characteristics and seasonal variability of tidal wind oscillations in the MLT region over Trivandrum (8.5° N, 77° E): first results from SKiYMET Meteor Radar

et al. 2006

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Abstract. Tidal activity in the Mesospheric Lower Thermosphere (MLT) region over Trivandrum (8.5 • N, 77 • E) is investigated using the observations from newly installed SKiYMET Meteor Radar. The seasonal variability and vertical propagation characteristics of atmospheric tides in the MLT region are addressed in the present communication.The observations revealed that the diurnal tide is more prominent than the semi/terdiurnal components over this latitude. It is also observed that the amplitudes of meridional components are stronger than that of zonal ones. The amplitude and phase structure shows the vertical propagation of diurnal tides with vertical wavelength of ∼25 km. However, the vertical wavelength of the semidiurnal tide showed considerable variations. The vertical propagation characteristics of the terdiurnal tide showed some indications of their generating mechanisms. The observed features of tidal components are compared with Global Scale Wave Model (GSWM02) values and they showed a similar amplitude and phase structure for diurnal tides. Month-to-month variations in the tidal amplitudes have shown significant seasonal variation. The observed seasonal variation is discussed in light of the variation in tidal forcing and dissipation.

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Section: Diurnal Tidessupporting

confidence: 81%

Vertical propagation characteristics and seasonal variability of tidal wind oscillations in the MLT region over Trivandrum (8.5° N, 77° E): first results from SKiYMET Meteor Radar

et al. 2006

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“…subsequent works including analyses of GCM outputs (i.e., Tokioka and Yagai, 1987;Yagai, 1989). Subsequent numerical modeling efforts noted the probable importance of nonmigrating tides to the dynamics of the mesosphere and lower thermosphere (i.e., Forbes and Groves, 1987;Williams and Avery, 1996;Kattatov et al, 1996;Ekanayake et al, 1997;Miyahara et al, 1993Miyahara et al, , 1999Miyahara and Miyoshi, 1997) consistent with contemporaneous analyses of satellite measurements (i.e., Lieberman, 1991;Hagan et al, 1997;Talaat and Lieberman, 1999). This general conclusion is now supported more definitively by a number of very recent model results (i.e., Hagan and Roble, 2001;Hagan and Forbes, 2002;Forbes et al, 2001;Angelats i Coll and Forbes, 2002;Grieger et al, 2002;Yamashita et al, 2002) and satellite data analyses (i.e., Angelats i Coll and Forbes et al, 2002;Manson et al, 2003;Oberheide et al, 2002).…”

Section: And In Many Othermentioning

confidence: 99%

Diurnal nonmigrating tides in the tropical lower thermosphere

et al. 2014

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A comparison is performed between monthly-mean nonmigrating diurnal tide wind components at 95 km derived from Upper Atmosphere Research Satellite (UARS) wind observations, the Middle Atmosphere Circulation Model at Kyushu University (MACMKU), and the Global Scale Wave Model (GSWM) driven by latent heating due to deep tropical convection. A degree of overall agreement is obtained in the sense that annual-mean spectra at 95 km indicate that the UARS data, MACMKU and GSWM all share the same nonmigrating tide components (eastward-propagating with zonal wavenumber s = −3; westward-propagating with s = 2; standing or zonallysymmetric with s = 0; DE3, DW2, D0) at about the same power level. In combination with the migrating tide these wave components give rise to significant longitude variability in the total diurnal tidal fields. Beyond the above model/measurement agreements, significant discrepancies remain between the latitudinal-seasonal structures delineated by models and observation. For MACMKU, some of these discrepancies may be related to the specifics of the convective parameterization that is employed. Significant work remains to better delineate tropospheric forcing mechanisms and nonlinear wave-wave interactions as sources for nonmigrating tides.

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“…For similar reasons, this mode was included for diurnal cloud heating, which is expected to have a very narrow heating region in the vertical direction. However, although we have neglected the non-migrating modes of water vapour heating, they could become important in the mesospheric-lower thermospheric region (Forbes and Groves, 1987). For all the seasons, only one simulation was done using an average diurnal heating rate for different heat sources.…”

Section: Simulation Of Tidal Fields Using Classical Tidal Theorymentioning

confidence: 99%

“…These Sun-asynchronous tidal modes are known as nonmigrating modes. Non-migrating tides may also be generated by any other zonally asymmetric diurnally varying heat sources such as planetary boundary layer heat flux (Mckenzie, 1968;Kato et al, 1982;Tsuda and Kato, 1989), solar radiation absorption by zonally varying water vapour (Forbes and Groves, 1987), latent heat release in deep convective clouds and solar radiation absorption by zonally varying water vapour (Williams and Avery, 1996;Hagan et al, 1997). Recently, Lieberman and Leovy (1995) and Ekanayake et al (1997), have done numerical studies of non-migrating tides by incorporating a combination of these different diurnal heat sources.…”

Section: Introductionmentioning

confidence: 99%

Tidal wind oscillations in the tropical lower atmosphere as observed by Indian MST Radar

2001

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Abstract. Diurnal tidal components in horizontal winds measured by MST radar in the troposphere and lower stratosphere over a tropical station Gadanki (13.5 • N, 79.2 • E) are presented for the autumn equinox, winter, vernal equinox and summer seasons. For this purpose radar data obtained over many diurnal cycles from September 1995 to August 1996 are used. The results obtained show that although the seasonal variation of the diurnal tidal amplitudes in zonal and meridional winds is not strong, vertical phase propagation characteristics show significant seasonal variation. An attempt is made to simulate the diurnal tidal amplitudes and phases in the lower atmosphere over Gadanki using classical tidal theory by incorporating diurnal heat sources, namely, solar radiation absorption by water vapour, planetary boundary layer (PBL) heat flux, latent heat release in deep convective clouds and short wave solar radiation absorption by clouds. A comparison of the simulated amplitudes and phases with the observed ones shows that agreement between the two is quite good for the equinox seasons, especially the vertical structure of the phases of the meridional wind components.

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Diurnal propagating tides in the low-latitude middle atmosphere

Cited by 46 publications

References 17 publications

Vertical propagation characteristics and seasonal variability of tidal wind oscillations in the MLT region over Trivandrum (8.5° N, 77° E): first results from SKiYMET Meteor Radar

Vertical propagation characteristics and seasonal variability of tidal wind oscillations in the MLT region over Trivandrum (8.5° N, 77° E): first results from SKiYMET Meteor Radar

Diurnal nonmigrating tides in the tropical lower thermosphere

Tidal wind oscillations in the tropical lower atmosphere as observed by Indian MST Radar

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