Theoretical studies of atmospheric tides

Forbes, Jeffrey M.; Garrett, Henry

doi:10.1029/rg017i008p01951

Cited by 237 publications

(159 citation statements)

References 116 publications

Supporting

Mentioning

145

Contrasting

Unclassified

Order By: Relevance

“…The theory and observation of the atmospheric tides have been ably reviewed many times (Siebert, 1961;Chapman and Lindzen, 1970;Lindzen and Chapman, 1971;Forbes andGarrett, 1978, Kato, 1980). Classical tidal theory applies to oscillations of a stationary, inviscid, spherically symmetric thin atmosphere; meridional temperature gradients and mean winds are neglected.…”

Section: Tidal Resonancementioning

confidence: 99%

A constant daylength during the precambrian era?

Zahnle

Walker

1987

Precambrian Research

View full text Add to dashboard Cite

Zahnle, K. and Walker, J.C.G., 1987. A constant daylength during the Precambrian Era? Precambrian Res., 37: 95-105.The semidiurnal atmospheric thermal tide would have been resonant with free oscillations of the atmosphere when the day was ~ 21 h long, c. 600 Ma ago. Very large atmospheric tides would have resulted, with associated surface pressure oscillations in excess of 10 mbar in the tropics. Near resonance the Sun's gravitational torque on the atmospheric tide -accelerating Earth's rotation -would have been comparable in magnitude to the decelerating lunar torque upon the oceanic tides. The balance of the opposing torques may have long maintained a resonant ~ 21 h day, perhaps for much of the Precambrian. Because the timescale of lunar orbital evolution is not directly affected, a constant daylength would result in fewer days/month. The hypothesis is shown not to conflict with the available (stromatolitic) evidence. Escape from the resonance could have followed a relatively abrupt global warming, such as that occurring at the end of the Precambrian. Alternatively, escape may simply have followed a major increase in the rate of oceanic tidal dissipation, brought about by the changing topography of the world's oceans. We integrate the history of the lunar orbit with and without a sustained resonance, finding that the impact of a sustained resonance on the other orbital parameters of the Earth-Moon system would not have been large.

show abstract

Section: Tidal Resonancementioning

confidence: 99%

A constant daylength during the precambrian era?

Zahnle

Walker

1987

Precambrian Research

View full text Add to dashboard Cite

show abstract

“…The absorption of solar radiation by a zonally uniform medium gives rise to migrating solar tides. Their presence in the atmosphere is due to the tropospheric water vapor (H 2 O) absorption of infrared radiation (IR), stratospheric and lower mesospheric ozone (O 3 ) absorption of ultraviolet (UV) radiation, mesospheric molecular oxygen (O 2 ) absorption in the Schumann-Runge bands and continuum, and thermospheric oxygen absorption of extreme ultraviolet (EUV) radiation (Chapman and Lindzen, 1970;Forbes and Garret, 1979;Groves, 1982a, b). The release of latent heat by deep convective clouds is another possible source that could generate nonnegligible tidal migrating and nonmigrating response in the MLT (Hamilton, D. Pancheva et al: Migrating semidiurnal tide in the SABER/TIMED temperatures 1981; Williams and Avery, 1996;Hagan, 1996;Forbes et al, 1997;Hagan and Forbes, 2003).…”

Section: Introductionmentioning

confidence: 99%

Global structure, seasonal and interannual variability of the migrating semidiurnal tide seen in the SABER/TIMED temperatures (2002–2007)

2009

View full text Add to dashboard Cite

Abstract. The present paper is focused on the global spatial (altitude and latitude) structure, seasonal and interannual variability of the migrating semidiurnal tide derived from the SABER/TIMED temperature measurements for 6 years (January 2002-December 2007. The tidal results are obtained by a new analysis method where the tides (migrating and nonmigrating) and the planetary waves (zonally travelling and stationary) are simultaneously extracted from the satellite data. The strongest migrating semidiurnal tide has been derived at tropical latitudes (±20-30 • ) where it revealed significant amplification between May and August in the lower thermosphere of both hemispheres. On the average, the semidiurnal temperature tide is stronger in the SH (32 K) than that in the NH (30 K) and the tidal amplitudes at 110 km height are nearly a factor of 5 larger than those at 90 km. The migrating semidiurnal tide in both hemispheres revealed remarkable seasonal behavior at the altitude where it maximizes, ∼110 km in the NH and ∼115 km in the SH, indicating repeatable each year maxima exactly in May-June and August. However, while the main maximum in the NH is that in August, in the SH it is that in May. The vertical wavelengths indicated seasonal variability being larger in summer (∼38-50 km) than in winter (∼25-35 km). The seasonal behavior of the semidiurnal tide in the middle latitudes (±40 • ) is dominated by annual variability with a winter maximum in the upper mesosphere (90 km) of both hemispheres and summer one in the lower thermosphere (110 km). The NH summer maximum (June and August peaks) is much stronger than that in the SH (November and March peaks) having amplitudes of ∼23 K and ∼13-15 K respectively. The vertical wavelengths at both hemispheres indicated slight seasonal changes and a mean vertical wavelength of ∼35 km is observed during most of the year. The interannual variability of Correspondence to: D. Pancheva (dpancheva@geophys.bas.bg) the semidiurnal tide in the midlatitude lower thermosphere is at least partly connected with the stratospheric QBO as this effect is stronger in the NH.

show abstract

“…The expansion in longitude is performed in terms of exp(imλ), where m (= −6, ...+6) is a zonal wave number and λ is longitude. The coefficients of dynamic molecular viscosity and molecular thermal heat conduction were taken from Forbes and Garrett (1979), eddy viscosity was adopted from Hagan et al (1995) and hydromagnetic effects are included in a simple form as in Forbes and Garrett (1979). Some horizontal smoothing was applied to calculated fields that is equivalent to horizontal dissipation of the fourth order with a rate of about 10 15 m 4 /s.…”

Section: Appendixmentioning

confidence: 99%

High- and mid-latitude quasi-2-day waves observed simultaneouslyby four meteor radars during summer 2000

Merzlyakov

Pancheva²,

Mitchell³

et al. 2004

Ann. Geophys.

View full text Add to dashboard Cite

Abstract.Results from the analysis of MLT wind measurements at Dixon (73.5 • N, 80 • E), Esrange (68 • N, 21 • E), Castle Eaton (UK) (53 • N, 2 • W), and Obninsk (55 • N, 37 • E) during summer 2000 are presented in this paper. Using S-transform or wavelet analysis, quasi-two-day waves (QTDWs) are shown to appear simultaneously at high-and mid-latitudes and reveal themselves as several bursts of wave activity. At first this activity is preceded by a 51-53 h wave with S=3 observed mainly at mid-latitudes. After a short recess (or quiet time interval for about 10 days near day 205), we observe a regular sequence of three bursts, the strongest of them corresponding to a QTDW with a period of 47-48 h and S=4 at mid-altitudes.We hypothesize that these three bursts may be the result of constructive and destructive interference between several spectral components: a 47-48 h component with S=4; a 60-h component with S=3; and a 80-h component with S=2. The magnitudes of the lower (higher) zonal wave-number components increase (decrease) with increasing latitude. The S-transform or wavelet analysis indicates when these spectral components create the wave activity bursts and gives a range of zonal wave numbers for observed bursts from about 4 to about 2 for mid-and high-latitudes. The main spectral component at Dixon and Esrange latitudes is the 60-h oscillation with S=3. The zonal wave numbers and frequencies of the observed spectral components hint at the possible occurrence of the nonlinear interaction between the primary QTDWs and other planetary waves. Using a simple 3-D nonlinear numerical model, we attempt to simulate some of the observed features and to explain them as a consequence of the nonlinear interaction between the primary 47-48 h and the 9-10 day waves, and the resulting linear superposition of primary and secondary waves. In addition to the QTDW bursts, we also infer forcing of the 4-day wave with S=2 and the 6-7 day wave with S=1, possibly arising from nonlinear decoupling of the 60-h wave with S=3. The starting mechanism for this decoupling is the Rossby wave instability (e.g.Correspondence to: E. Merzlyakov (eugmer@typhoon.obninsk.org) Baines, 1976). This result is consistent with the day-to-day wind variability during the observed QTDW events. An interesting feature of the final stage of the observed QTDW activity in summer 2000 is the occurrence of strong 4-5 day waves with S=3.

show abstract

Theoretical studies of atmospheric tides

Cited by 237 publications

References 116 publications

A constant daylength during the precambrian era?

A constant daylength during the precambrian era?

Global structure, seasonal and interannual variability of the migrating semidiurnal tide seen in the SABER/TIMED temperatures (2002–2007)

High- and mid-latitude quasi-2-day waves observed simultaneouslyby four meteor radars during summer 2000

Contact Info

Product

Resources

About