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Atmospheric Tides

Migrating tides, Migrating tide in CRISTA-1 data, Nonmigrating tides, References

Migrating tides

Migrating solar tides persist throughout the middle atmosphere and become one of the most striking features in the upper mesosphere and lower thermosphere (MLT). They are global-scale waves with periods that are subharmonics of a solar day and propagate westward with the apparent motion of the sun. Some basic features of the diurnal and semidiurnal tidal components can be described by classical tidal theory [e.g. Chapman and Lindzen, 1970] but for a more quantitative understanding a realistic background atmosphere as well as an appropriate parameterization of tidal forcing and dissipation have to be taken into account.
The amount of data available for tidal analysis on a global scale has significantly increased in the past few years. This motivated the development of numerical models which include realistic background wind and temperature fields in combination with improved tidal forcing and dissipation. In particular, ground-based wind and temperature measurements have been used to develop tidal climatologies and to establish the spatial and temporal characteristics of the tides [e.g. Chang and Avery, 1997; Fritts and Isler, 1994; Gille et al., 1991; Manson et al., 1989; Vincent et al., 1989].
The first global measurement of atmospheric tides was obtained by using temperature data from the Limb Infrared Monitor of the Stratosphere instrument (LIMS) on the Nimbus 7 satellite. Hitchman and Leovy [1985] showed that basic tidal signatures deduced from the day/night temperature differences are consistent with model predictions [Forbes, 1982] of the first symmetric propagating mode of the diurnal tide. Wind observations from the High Resolution Doppler Imager (HRDI) [Hays et al., 1993] and the Wind Imaging Interferometer (WINDII) [Shepherd et al., 1993] on the Upper Atmosphere Research Satellite (UARS) were used to study the seasonal dependence of the diurnal and semidiurnal tide [Burrage et al., 1995a, b; McLandress et al., 1996] and the interannual variability [Burrage et al., 1995a]. Temperature measurements from the Improved Stratospheric and Mesospheric Sounder (ISAMS) on UARS confirmed the LIMS results [Dudhia et al., 1993]. In contrast, Wu et al. [1998] reported on trapped modes in the equatorial diurnal tide evident in temperature data from the Microwave Limb Sounder (MLS, [Barath et al., 1993]) on UARS. The UARS data have been primarily used to improve the tidal forcing and dissipation, and the background temperature and wind fields used in earlier modeling work [e.g. Forbes, 1984; Vial, 1989]. Khattatov et al. [1997] derived tidal dissipation from HRDI measurements using a linear model. Geller et al. [1997] showed that dissipation in the MLT region is a major controlling factor in the annual variation of the diurnal tide. They replaced the tidal dissipation in the global-scale wave model (GSWM-95, [Hagan et al., 1995]) with the Khattatov values and achieved better agreement between the resultant calculation and the HRDI measurements. Yudin et al. [1998] used the tuned mechanistic tidal model (TMTM) to evaluate tidal dissipation and background zonal winds from UARS wind data and demonstrated the consistency of the tides observed in HRDI/WINDII temperature, airglow, and wind data. Ward [1999b] demonstrated that vertical advection associated with the migrating diurnal tide is the prime process causing local time variations in the airglow observations performed by WINDII and HRDI.
An alternate approach to determine self-consistent amplitudes and phases of the diurnal tide uses a tuned version of the recently revised global-scale wave model (GSWM-98, [Hagan et al., 1999a]) which includes tidal heating and dissipation schemes for November conditions. The model background atmosphere is updated using measurements of temperature, pressure, mass density, ozone, and geostrophic wind from the CRISTA experiment [Offermann et al., 1999] that was part of the US Space Shuttle mission STS-66. The high spatial resolution and the large vertical coverage of the CRISTA data provide a special opportunity to examine tidal signatures throughout the middle atmosphere. Although the local solar time coverage during the 7 days of measurements (Nov. 5-11, 1994) is too short for spectral analysis, tidal signatures can be estimated on a daily base by calculating the temperature differences between the zonal mean data from the ascending and descending portions of the orbits from 20 - 90 km altitude and from 52°S - 62°N. The ascending/descending temperature differences show a striking pattern of alternating positive and negative differences persisting throughout the mission. Ward et al. [1999a] showed that this feature is tidal in nature and consistent with the first symmetric propagating mode of the diurnal tide. These authors compared the CRISTA data to the GSWM-95 predictions for equinox conditions and found good qualitative agreement but also quantitative differences in the equatorial amplitude and phase distributions. By comparing CRISTA measurements and GSWM-95 predictions in terms of equivalent vertical displacement, they attribute the deviations to the climatological temperature and wind fields assumed in the GSWM-95 calculations. The following results quantify this sensitivity of model/observation intercomparisons to realistic atmospheric background conditions. The examination of any remaining differences may provide further insight into tidal dissipation and/or coupling with other waves. The complete paper by Oberheide et al. [2000] can be found here.



Migrating tides: Selected results from CRISTA 1

migrating diurnal tide
 The migrating diurnal tide at 7.5oN as measured by the CRISTA-1 instrument during 9 November 1994. The animation (1.2 MB) shows the temperature perturbation as function of local time and was computed by using the measured tidal amplitude and phase. Please note that the downward phase progression corresponds to upward energy propagation. The dashed lines indicate exponential amplitude growth. Wave breaking/dissipation ocurrs above the mesopause.
GSWM model runs for CRISTA 1 (part a)

GSWM ascending/descending orbit portion temperature differences for the diurnal tide, calculated for the LST's of CRISTA-1 measurements taken on November 9, 1994. The contour interval is 2 K. All model runs show a pattern of alternating positive (solid lines) and negative (dashed lines) values characteristic of the first symmetric propagating mode of the diurnal tide. (upper left) GSWM-98 for equinox (October) conditions. (upper right) GSWM-98 with climatological values for November. (lower left) Same as upper right but with CRISTA geostrophic zonal wind. (lower right) Same as lower left but with CRISTA geostrophic wind and temperature. Click on image for larger figure.
GSWM model runs for CRISTA 1 (part b)

(upper left) CRISTA-1 ascending/descending orbit portion difference for November 9, 1994. (upper right) GSWM-98 diurnal prediction updated with zonal wind, temperature, pressure, density and ozone concentration from the CRISTA measurements. (lower left) Same as upper right but for the semi-diurnal component. (lower right) Diurnal and semi-diurnal component. This panel suggests that GSWM predicts the semi-diurnal component less well than the diurnal mode. Click on image for larger figure.
Equatorial CRISTA-1diurnal tidal amplitudes and phases

(left) Phases of the diurnal tide for the 0°-10°N latitudinal band. (right) Amplitudes of the diurnal tide for 0°-10°N latitudinal band. Symbols mark CRISTA results; dotted lines indicate GSWM prediction for equinox (October) conditions. GSWM with climatological November values (base case) is indicated by dashed lines, and solid lines show the model predictions for the updated background atmosphere (final case). Dashed-dotted lines indicate the model results with CRISTA geostrophic zonal wind, and dashed-dotted-dotted-dotted lines are the model results with CRISTA wind and temperature. The background atmosphere update, particularly the wind update, significantly increases the phase predictions. The observed amplitudes decrease above 75 km. This is not observed in the model. Click on image for larger figure.



References

Barath, F. T., et al., The Upper Atmosphere Research Satellite Microwave Limb Sounder Instrument, J. Geophys. Res., 98, 10,751-10,762, 1993.

Burrage, M. D., M. E. Hagan, W. R. Skinner, D. L. Wu, and P. B. Hays, Long-term variability in the solar diurnal tide observed by HRDI and simulated by the GSWM, Geophys. Res. Lett., 22, 2641-2644, 1995a.

Chang, J. L., and S. K. Avery, Observations of the diurnal tide in the mesosphere and lower thermosphere over Christmas Island, J. Geophys. Res., 102, 1895-1907, 1997.

Chapman, S., and R. S. Lindzen, Atmospheric tides, D. Reidel Publ., Ma., 1970.

Dudhia, A., S. E. Smith, A. R. Wood and F. W. Taylor, Diurnal and semi-diurnal temperature variability of the middle atmosphere, as observed by ISAMS, Geopyhs. Res. Lett., 20, 1251-1254, 1993.

Forbes, J. M., Atmospheric tides, 1, Model description and results for the solar diurnal component, J. Geophys. Res., 87, 5222-5240, 1982.

Forbes, J. M., Middle atmosphere tides, J. Atmos. Terr. Phys., 46, 1049-1067, 1984.

Fritts, D. C, and J. R. Isler, Mean Motions and Tidal and Two-Day Structure and Variability in the Mesosphere and Lower Thermosphere over Hawaii, J. Atmos. Sci., 51, 2145-2164, 1994.

Geller, M. A., V. A. Yudin, B. V. Khattatov, and M. E. Hagan, Modeling the diurnal tide with dissipation derived from UARS/HRDI measurements, Ann. Geophys., 15, 1198-1204, 1997.

Gille, S. T., A. Hauchecorne, and M.-L. Chanin, Semidiurnal and Diurnal Tidal Effects in the Middle Atmosphere as Seen by Rayleigh Lidar, J. Geophys. Res., 96, 7579-7587, 1991.

Hagan, M. E., J. M. Forbes, and F. Vial, On modeling migrating solar tides, Geophys. Res. Lett., 22, 893-896, 1995.

Hagan, M. E., M. D. Burrage, J. M. Forbes, J. Hackney, W. J. Randel, and X. Zhang, GSWM-98: Results for migrating solar tides, J. Geophys. Res., 104, 6813-6828, 1999a.

Hays, P. B., V. J. Abreu, M. E. Dobbs, D. A. Gell, H. J. Grassl, and W. R. Skinner, The High Resolution Doppler Imager on the Upper Atmosphere Research Satellite, J. Geophys. Res., 98, 10,713-10,723, 1993.

Hitchman, M. H., and C. B. Leovy, Diurnal Tide in the Equatorial Middle Atmosphere as Seen in LIMS Temperatures, J. Atmos. Sci., 42, 557-561, 1985.

Khattatov, B. V., M. A. Geller, and V. A. Yudin, Diurnal migrating tide as seen by the high-resolution Doppler imager/UARS; 2. Monthly mean global zonal and vertical velocities, pressure, temperature, and inferred dissipation, J. Geophys. Res., 102, 4423-4435, 1997.

Manson, A. H., C. E. Meek, H. Teitelbaum, F. Vial, R. Schminder, D. Kürschner, M. J. Smith, G. J. Fraser, and R. R. Clark, Climatologies of semi-diurnal tides in the middle atmosphere (70-110 km) at middle latitudes (40-55°), J. Atmos. Terr. Phys., 51, 579-593, 1989.

McLandress, C., G. G. Shepherd, and B. H. Solheim, Satellite observations of thermospheric tides: Results from the Wind Imaging Interferometer on UARS, J. Geophys. Res., 101, 4093-4114, 1996.

Oberheide, J., M. E. Hagan, W. E. Ward, M. Riese, and D. Offermann, Modeling the diurnal tide for the Cryogenic Infrared Spectrometers and Telscopes for the Atmosphere (CRISTA) 1 time period, J. Geophys. Res., 105, 24,917-24,929, 2000.

Offermann, D., K.-U. Grossmann, P. Barthol, P. Knieling, M. Riese, and R.Trant, The CRyogenic Infrared Spectrometers and Telescopes for the Atmosphere (CRISTA) experiment and middle atmosphere variability, J. Geophys. Res., 104, 16,311-16,325, 1999.

Shepherd, G. G., et al., WINDII, the Wind Imaging Interferometer on the Upper Atmosphere Research Satellite, J. Geophys. Res., 98, 10,725-10,750, 1993.

Vial, F., Tides in the middle atmosphere, J. Atmos. Terr. Phys., 51, 3-17, 1989.

Vincent, R. A., T. Tsuda, and S. Kato, Asymmetries in mesospheric tidal structure, J. Atmos. Terr. Phys., 51, 609-616, 1989.

Ward, W. E., J. Oberheide, M. Riese, P. Preusse, and D. Offermann, Tidal Signatures in Temperature Data from the CRISTA I Mission, J. Geophys. Res., 104, 16,391-16,403, 1999a.

Ward, W. E., A simple model of diurnal variations in the mesospheric oxygen nightglow, Geopyhs. Res. Lett., 26, 3565-3568, 1999b.

Wu, D. L., C. McLandress, W. G. Read, J. W. Waters, and L. Froideaux, Equatorial diurnal variations observed in UARS Microwave Limb Sounder temperature during 1991-1994 and simulated by the Canadian Middle Atmosphere Model, J. Geophys. Res., 103, 8909-8917, 1998.

Yudin, V. A., M. A. Geller, B. V. Khattatov, D. A. Ortland, M. D. Burrage, C. McLandress, G. G. Shepherd, TMTM simulations of tides: Comparison with UARS observations, Geopyhs. Res., Lett., 25, 221-224, 1998.