Internal Gravity Wave Selection in the Upper Troposphere and Lower Stratosphere Observed by the MU Radar: Preliminary Results

Yamanaka, Manabu D.; Fukao, S.; Matsumoto, H.; Sato, Toru; Tsuda, Toshitaka; Katō, Susumu

doi:10.1007/978-3-0348-5825-0_20

Cited by 7 publications

(9 citation statements)

References 30 publications

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“…Analyzing the dominant component of IGWs with short vertical wave length (≤4 km) and long ground-based period (≥10 h) in the lower stratosphere and upper troposphere over Shigaraki Japan, Sato (1994) found that in winter IGWs propagated generally southward in the 12-18 km region, while westward IGWs were dominant at 18-22 km. In contrast to these observations (Hirota and Niki, 1986;Yamanaka et al, 1989;Sato, 1994) of IGWs propagating transverse to the jet stream, radar measurements (Thomas et al, 1999) at Aberystwyth (52.4 • N, 4.1 • W) of winds at tropospheric and lower stratospheric heights indicated inertia-gravity waves propagating in a direction similar to that of the jet stream but at smaller velocities.…”

Section: Introductioncontrasting

confidence: 63%

“…Hirota and Niki, 1986;Yamanaka et al, 1989). Analyzing the dominant component of IGWs with short vertical wave length (≤4 km) and long ground-based period (≥10 h) in the lower stratosphere and upper troposphere over Shigaraki Japan, Sato (1994) found that in winter IGWs propagated generally southward in the 12-18 km region, while westward IGWs were dominant at 18-22 km.…”

Section: Introductionmentioning

confidence: 99%

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Statistical characteristics of AGW wave packet propagation in the lower atmosphere observed by the MU radar

et al. 2009

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Abstract. We study the horizontal structure of the atmospheric gravity waves (AGW) in the height ranges between 6 and 22 km observed using the MU radar at Shigaraki in Japan, during a 3 day period in January and a 4 day period in August 1988. The data were divided by double Fourier transformation into a data set of upward moving waves and a data set of downward moving waves for independent analysis. The phase and group velocity tracing technique was applied to measure the vertical group and phase velocity as well as the characteristic period of the gravity wave packet. Then the dispersion equation of the linear theory of AGW was solved to obtain its intrinsic wave period -horizontal wavelength and horizontal group velocity -and the vertical flux of horizontal momentum associated with each wave packet was estimated to help determine the direction of the characteristic horizontal wave vector. The results showed that the waves with periods in the range of 30 min∼6 h had horizontal scales ranging from 20 km to 1500 km, vertical scales from 4 km to 15 km, and horizontal phase velocities from 15 m/s to 60 m/s. The upward moving wave packets of wave period of 2 h∼6 h had horizontal group velocities mainly toward eastsouth-east and northeast in winter, and mainly in the section between the directions of west-north-west and north in summer.

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Section: Introductioncontrasting

confidence: 63%

Section: Introductionmentioning

confidence: 99%

Statistical characteristics of AGW wave packet propagation in the lower atmosphere observed by the MU radar

et al. 2009

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“…In this case, the c h −U >0 waves, together with the decrease in the mean zonal wind with height, in the height interval of spectral analysis, act collectively to produce β = -1 (downshifting). On the other hand, the observations have shown that gravity waves are also produced near the jet stream peak at ∼10 km (Yamanaka et al, 1989;Fritts and Nastrom, 1992;Sato, 1994), and these waves can enter the stratosphere where they yield β = -1 (downshifting). However, the lower tropospheric waves cannot enter the stratosphere due to criticallevel encounters lower down.…”

Section: Spectral Amplitudesmentioning

confidence: 99%

Spectral analysis of 10-m resolution temperature profiles from balloon soundings over Beijing

Xu²,

Yuan³

et al. 2006

Ann. Geophys.

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Abstract. Vertical temperature profiles with a height resolution of 10 m have been measured in the troposphere and lower stratosphere during March and April 2003 over the Beijing Meteorological Observatory. This resolution allows us to study temperature spectra up to higher wave numbers than many published papers. Our purposes in this study are to examine the spectral character of normalized temperature fluctuations in the 2.90-8.01 km (troposphere) and 14.65-19.76 km (lower stratosphere) altitude ranges and to compare them with model spectra. Vertical wave number spectra of six temperature profiles are presented. Results indicate that mean spectral slopes are about −1.9 in the troposphere and −2.2 in the lower stratosphere, which is believed to be the shallowest slopes ever measured by balloonborne radiosonde soundings. Mean spectral amplitudes at m=1/(100 m) are about 17 times larger in the troposphere and 4 times larger in the lower stratosphere than the predicted saturated spectral amplitudes. These results show that the observed temperature spectra do not obey current gravity wave saturation models, the "universal" atmospheric spectrum model, or the wind-shifting model, in both slope and amplitude.

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“…By this effect, cocan be smaller than the lower cut-off value (f, the Coriolis frequency) of the intrinsic frequency w (see, e.g., Yamanaka et al, 1989;Ogino et al,1995). Furthermore, by transience of the background field u (e.g., Tanaka, 1986), wave frequency w is not conserved in time.…”

Section: Two-dimensional Wavelet Analysismentioning

confidence: 98%

Application of Two-Dimensional Wavelet Analysis to Wind Disturbances Observed with MU Radar in the Lower Stratosphere and Troposphere

Shimomai

Yamanaka

Fukao

1997

J. geomagn. geoelec

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Orthonormal wavelet analysis is applied for the first time to two-dimensional (time and height) data obtained from three-week continuous MU radar observations in June-July, 1991. It is confirmed that monochromatic wave structures are generally localized both in time and in altitude. We find the dominant temporal scale of wave activity in this case study is 2-4 days. The dominant vertical wavelength seems to decrease from -4 km to -1 km, upwards through the tropopause-lower stratosphere region, which is almost independent of temporal scales in the 1-4 day range.

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Internal Gravity Wave Selection in the Upper Troposphere and Lower Stratosphere Observed by the MU Radar: Preliminary Results

Cited by 7 publications

References 30 publications

Statistical characteristics of AGW wave packet propagation in the lower atmosphere observed by the MU radar

Statistical characteristics of AGW wave packet propagation in the lower atmosphere observed by the MU radar

Spectral analysis of 10-m resolution temperature profiles from balloon soundings over Beijing

Application of Two-Dimensional Wavelet Analysis to Wind Disturbances Observed with MU Radar in the Lower Stratosphere and Troposphere

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