GSWM‐98: Results for migrating solar tides

Hagan, M. E.; Burrage, M. D.; Forbes, Jeffrey M.; Hackney, Jeremy Keith; Randel, William J.; Zhang, X.

doi:10.1029/1998ja900125

Cited by 332 publications

(379 citation statements)

References 36 publications

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“…For the GSWM and CRISTA comparisons reported herein, we were motivated to calculate a GSWM tidal climatology appropriate for November conditions. The GSWM-98 climatological diurnal tidal predictions for October are probably inadequate indicators of the solar migrating tide during November, because the migrating diurnal tide is strongly affected by the zonal mean zonal wind field [Hagan et al, 1999a] (Figure 7) below 90 km also compare qualitatively well to the derived geostrophic wind field. It is quite interesting that the SH tropical wind maximum in the mesosphere is present in both data sets (but less pronounced in GRAM-95).…”

Section: Measurementssupporting

confidence: 55%

“…As pointed out by Hagan et al [1999a], the diurnal tidal response during equinox conditions is largely attributable to the zonal wind in the stratosphere. Figure 12 illustrates that the equatorial wind field differences between GSWM-98 and the base case calculations are rather small in this altitude regime.…”

Section: Discussionmentioning

confidence: 99%

“…They used an analytic approach to quantify the structure of the diurnal tidal solution by introducing a Doppler-shifted complex tidal frequency, and they found that eastward (westward) mean winds effectively lengthen (shorten) Xz. Hagan et al [1999b] showed that the assumptions inherent in the Forbes and Vincent formulation preclude its use for the interpretation of the GSWM results because the GSWM parameterizations of molecular viscosity and eddy diffusivity [Hagan et al, 1999a] indicate that there is a feedback between the modifications to the tide attributable to vertical wavelength distortions and modifications attributable to dissipative effects. This feedback is neglected in the analytic formulation and must account for the phase differences observed in the GSWM results from the successive model updates.…”

Section: Discussionmentioning

confidence: 99%

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Modeling the diurnal tide for the Cryogenic Infrared Spectrometers and Telescopes for the Atmosphere (CRISTA) 1 time period

Oberheide¹,

Hagan²,

Ward³

et al. 2000

J. Geophys. Res.

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Abstract. High-resolution stratospheric and mesospheric temperature measurements from the Cryogenic Infrared Spectrometers and Telescopes for the Atmosphere (CRISTA) experiment taken during the space shuttle mission STS 66 in November 1994 show large tidal signatures in the day/night temperature differences. Previous comparisons with the predictions of the global-scale wave model (GSWM-95) for equinox conditions have shown these differences to be in very good qualitative agreement with GSWM results for the diurnal component of the migrating solar tide, although quantitative differences in the tidal amplitudes and phases did exist. In this paper the source of these differences is examined. Background fields corresponding to the flight conditions are derived from the CRISTA data and used as input to an updated version of the GSWM. The updated GSWM includes revised tidal heating and dissipation schemes. The background fields from CRISTA include temperature, ozone, pressure, mass density, and derived geostrophic wind (in geostrophic balance with the CRISTA temperatures). These model updates significantly improve the agreement with the CRISTA observations at all latitudes and altitudes. Modeled and observed phases match to within 1 hour at the equator. The amplitudes agree within 1 K for most altitudes. Above 75 km, however, the CRISTA measurements show a decrease in the tidal amplitude which is not present in the GSWM results, suggesting that the model underestimates the equatorial gravity wave dissipation in the form of eddy diffusivity and wave stress in the upper mesosphere. The mesospheric wind field update accounts for the most profound improvement in the phase distributions of the diurnal tide. The results show the strengths of the GSWM but also indicate the need for some model improvements. Our determination of the GSWM capability for reliable predictions of phases and amplitudes of the migrating diurnal tide when realistic atmospheric background conditions are used, provides some guidance in the way such models should be used in the future. In addition, the understanding of the diurnal cycle of chemical active species requires an accurate tidal prediction, due to the temperature dependencies of the reactions and the transport processes associated with the tides.

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Section: Measurementssupporting

confidence: 55%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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Modeling the diurnal tide for the Cryogenic Infrared Spectrometers and Telescopes for the Atmosphere (CRISTA) 1 time period

Oberheide¹,

Hagan²,

Ward³

et al. 2000

J. Geophys. Res.

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show abstract

“…Properties of the semidiurnal tides propagating up from the lower atmosphere are generally unknown for specific simulation intervals, and are specified at the lower boundary of the TIME-GCM (e.g. Fesen et al, 1986) using seasonal averages derived from the Global Scale Wave Model of Hagan et al (1999), although they can be tuned for specific dates if sufficient tidal data are available.…”

Section: Thermosphere-ionosphere-mesosphereelectrodynamics Genaral CImentioning

confidence: 99%

Studies of ionospheric F-region response in the Latin American sector during the geomagnetic storm of 21–22 January 2005

et al. 2011

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Abstract. In the present investigation, we have studied the response of the ionospheric F-region in the Latin American sector during the intense geomagnetic storm of 21-22 January 2005. This geomagnetic storm has been considered "anomalous" (minimum Dst reached −105 nT at 07:00 UT on 22 January) because the main storm phase occurred during the northward excursion of the B z component of interplanetary magnetic fields (IMFs). The monthly mean

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“…However, the day-to-day variability is mainly because of the variability in the tidal structure, which also exhibits large seasonal variability [Deepa et al, 2006]. Tides have horizontal wind amplitudes that can exceed 50 m/s and temperature amplitudes of as much as 20 K at upper mesospheric altitudes [Hagan et al, 1999]. Tidal amplitudes increase with altitude up to the lower thermosphere and vary somewhat regularly with season.…”

Section: Introductionmentioning

confidence: 99%

Planetary wave-tidal interactions over the equatorial mesosphere-lower thermosphere region and their possible implications for the equatorial electrojet

et al. 2011

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[1] Optically measured daylight mean mesopause temperatures over a dip equatorial station, Trivandrum (8.5°N; 77°E; dip lat. 0.5°N), have been analyzed in conjunction with simultaneously measured equatorial electrojet (EEJ)-produced magnetic field at the surface. The signature of planetary wave-tidal interactions in the mesosphere-lower thermosphere (MLT) region has been observed for the first time in the day-to-day variability in the EEJ, i.e., the time of its peaking and the duration, as inferred from the EEJ-produced magnetic field on the ground. The present study shows that the planetary wave of quasi 16 day periodicity plays an important role in causing these variabilities, especially during the winter months. The quasi 16 day wave is found to be modulating the mesopause temperature (MT), duration, and time of the maximum EEJ intensity (D EEJ and T EEJ ). During positive excursions of the planetary wave, T EEJ showed a shift toward evening, while the MT showed an increase and D EEJ showed a broadening. Similarly, all these parameters exhibited an opposite trend during negative excursions. The planetary wave-tidal interactions and subsequent modification of the tidal components have been shown to be responsible for the observed variations. This study presents a new perspective addressing the day-to-day variability of the EEJ.

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GSWM‐98: Results for migrating solar tides

Cited by 332 publications

References 36 publications

Modeling the diurnal tide for the Cryogenic Infrared Spectrometers and Telescopes for the Atmosphere (CRISTA) 1 time period

Modeling the diurnal tide for the Cryogenic Infrared Spectrometers and Telescopes for the Atmosphere (CRISTA) 1 time period

Studies of ionospheric F-region response in the Latin American sector during the geomagnetic storm of 21–22 January 2005

Planetary wave-tidal interactions over the equatorial mesosphere-lower thermosphere region and their possible implications for the equatorial electrojet

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