Upper atmosphere tidal oscillations due to latent heat release in the tropical troposphere

Forbes, J. M.; Hagan, M. E.; Zhang, X.; Hamilton, Kevin

doi:10.1007/s005850050534

Cited by 31 publications

(50 citation statements)

References 9 publications

(11 reference statements)

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“…[16] The longitudinal distribution of tropospheric moist convection is considered to be one of the main causes for the generation of nonmigrating tides that propagate upward to the thermosphere [e.g., Forbes et al, 1997;Forbes, 2002, 2003]. In order to show the distribution of tropospheric moist convection as a tidal source, we carried out a Fourier filtering on the 30-day average rainfall rate to exhibit the amplitude of diurnal aggregate composed from the zonal wave numbers of −7 to +5 (Figure 4d).…”

Section: Resultsmentioning

confidence: 99%

“…In Figure 4d the rainfall rate increases in the equatorial region at separate longitude sectors, at about 70°W, 25°E, 110°E, and 150°E, where the vertical motion of atmosphere is enhanced, and the water vapor also increases, in the upper troposphere (not shown), thus indicating the region of active moist convection. In these regions atmospheric waves can be excited owing to latent heat release and insolation absorption by water vapor and clouds [e.g., Forbes et al, 1997;Forbes, 2002, 2003]. Figure 6 shows a plot similar to Figure 4d, but for the amplitude of rainfall rate combined from the diurnal migrating component (DW1) and the dominant nonmigrating component (DE3).…”

Section: Discussion and Summarymentioning

confidence: 99%

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Vertical connection from the tropospheric activities to the ionospheric longitudinal structure simulated by a new Earth's whole atmosphere-ionosphere coupled model

et al. 2011

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[1] This paper introduces a new Earth's atmosphere-ionosphere coupled model that treats seamlessly the neutral atmospheric region from the troposphere to the thermosphere as well as the thermosphere-ionosphere interaction including the electrodynamics selfconsistently. The model is especially useful for the study of vertical connection between the meteorological phenomena and the upper atmospheric behaviors. As an initial simulation using the coupled model, we have carried out a 30 day consecutive run in September. The result reveals that the longitudinal structure of the F-region ionosphere varies on a day-to-day basis in a highly complex way and that a four-peak structure of the daytime equatorial ionization anomaly (EIA) similar to the recent observations appears as an averaged feature. The simulation reproduces and thus confirms the vertical coupling processes proposed so far with respect to the formation of the averaged EIA longitudinal structure; the excitation of solar nonmigrating tides in the troposphere, their propagation through the middle atmosphere, and the modulation of ionospheric dynamo, which in turn affects EIA generation. The simulation result indicates that not only the ionospheric averaged longitudinal structure but also the day-to-day variation can be modulated significantly by the lower atmospheric effect.

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Section: Resultsmentioning

confidence: 99%

Section: Discussion and Summarymentioning

confidence: 99%

Vertical connection from the tropospheric activities to the ionospheric longitudinal structure simulated by a new Earth's whole atmosphere-ionosphere coupled model

et al. 2011

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“…Lindzen (1978) and Hong and Wang (1980) individually proposed that latent heat release associated with cloud and/or raindrop formation could be a significant tidal source. Subsequently, Forbes et al (1997) presented a correlative analysis on global cloud imagery (GCI) data and rain gauge data to verify that GCI is a viable proxy for rainfall rate. Since the simultaneous GCI data are not accessible to us, we need to acquire some information about the local latent heat release from other data.…”

Section: Diurnal Tidementioning

confidence: 99%

Intensive radiosonde observations of the diurnal tide and planetary waves in the lower atmosphere over Yichang (111°18' E, 30°42' N), China

Huang

Zhang

2009

Ann. Geophys.

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Abstract. The characteristics of diurnal tide and planetary waves (PWs) in the troposphere and lower stratosphere (TLS) over Yichang (111 • 18 E, 30 • 42 N) were studied by using the data from intensive radiosonde observations in August 2006 (summer month) and January 2007 (winter month) on an eight-times-daily basis. The radiosonde observations of the diurnal tide and PWs in the TLS in the mid-latitudes have seldom been reported. We find that there exists dominant diurnal oscillations in the TLS over Yichang. The observed diurnal tide consists of significant nonmigrating components, which may be owning to the local latent heat release. Since the nonmigrating tides are usually composed of high order modes with smaller vertical wavelengths, which are prone to dissipation in comparison with the low order modes, the observational tidal amplitudes decrease sharply at several heights. Some evident discrepancies between the observations and the GSWM-02 are found, which may result mainly from the inaccurate prediction of the nonmigrating tidal components by the GSWM-02. And, due to the evident seasonal differences of the water vapor mixing ratio disturbance and the tropospheric jet induced turbulence in winter, the diurnal tides in the summer and winter months have some different characteristics. Besides the diurnal tide, obvious quasi 7-day PW (QSDPW) and quasi 10-day PW (QTDPW) are also recognized from our observations in both the summer and winter months. The QSDPWs in the troposphere in both the summer and winter months show a standing wave structure, while the QTDPWs generally exhibit traveling wave characteristics. Spectral analyses reveal that some waves with periods around that of the diurnal tide Correspondence to: S. D. Zhang (zsd@whu.edu.cn) are generated due to the interactions of the diurnal tide and PWs and the tidal amplitudes are modulated by the PWs, indicating the extensive coupling between the diurnal tide and PWs. Moreover, our observations manifest that the PWs can exert great impacts on the tropospheric jet in winter and the tropopause in both the summer and winter months.

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“…from the Odin satellite (Llewellyn, 2002), can be expected to impact the modelling of the semidiurnal tide in the future. Forbes et al (2003) discuss the role and analysis of global cloud imagery data, which is related to deep convective activity and which can be converted to rainfall rate and latent heating (Forbes et al, 1997). (We occasionally use the abbreviation TLH, tropospheric latent heat, to categorize this hereafter.)…”

Section: Introductionmentioning

confidence: 99%

Global distributions of diurnal and semidiurnal tides: observations from HRDI-UARS of the MLT region and comparisons with GSWM-02 (migrating, nonmigrating components)

et al. 2004

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Abstract. HRDI (High Resolution Doppler Interferometer-UARS) winds data have been analyzed in 4• -latitude by 10 • -longitude cells at 96 km to obtain the global distribution of the solar-tidal amplitudes and phases. The solstices June-July (1993), December-January (1993-1994, and one equinox (September-October, 1994) are analyzed.In an earlier paper (Manson et al., 2002b) the emphasis was solely upon the longitudinal and latitudinal variations of the amplitudes and phases of the semidiurnal (12 h) and diurnal (24 h) tides. The longitudinal structures were shown to be quite distinctive, and in the case of the EW component of the diurnal tide there were typically four maxima/perturbations of amplitudes or phases around a latitude circle. In this case they tended to be associated with the locations of the major oceans. Here, a spatial complex spectral analysis has been applied to the data set, to obtain the zonal wave numbers for the tides as functions of latitude. For the diurnal tide the dominant s=1 migrating component and nonmigrating tides with wave numbers s=−3, −2, 0, 2 are identified; and for the semidiurnal tide, as well as the dominant s=2 migrating component, the spectra indicate the presence of nonmigrating tides with wave numbers s=−2, 0, 4. These wave numbers are also simply related to the global longitudinal structures in the tidal amplitudes and phases.Comparisons are made with the Global Scale Wave Model (GSWM-02), which now incorporates migrating and nonmigrating tides associated with tropospheric latent heat processes, and offers monthly outputs. For the diurnal tide the dominant nonmigrating tidal spectral feature (94 km) is for wave number s=−3; it is relatively stronger than in the HRDI winds, and produces quite consistent structures in the global tidal fields with four longitudinal maxima. Overall, the modelled 24-h tidal amplitudes are larger than observed during the equinox beyond 40 • latitude. For the semidiurnal tide, Correspondence to: A. H. Manson (manson@dansas.usask.ca) nonmigrating tides are frequently indicated in the spectra with wave numbers s=−2, 0, 6; and there are complementary longitudinal structures in the global tidal fields with two and four maxima evident. Modelled 12-h tidal amplitudes are much smaller than observed during non-winter months beyond 30 • . There is a detailed discussion of the spectral features, their seasonal variations, and the similarities with the HRDI tidal data. This discussion is in the context of the inherent limitations of the model.

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Upper atmosphere tidal oscillations due to latent heat release in the tropical troposphere

Cited by 31 publications

References 9 publications

Vertical connection from the tropospheric activities to the ionospheric longitudinal structure simulated by a new Earth's whole atmosphere-ionosphere coupled model

Vertical connection from the tropospheric activities to the ionospheric longitudinal structure simulated by a new Earth's whole atmosphere-ionosphere coupled model

Intensive radiosonde observations of the diurnal tide and planetary waves in the lower atmosphere over Yichang (111°18' E, 30°42' N), China

Global distributions of diurnal and semidiurnal tides: observations from HRDI-UARS of the MLT region and comparisons with GSWM-02 (migrating, nonmigrating components)

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