Time Sequence of Power Spectra of Disturbances in the Equatorial Lower Stratosphere in Relation to the Quasi-Biennial Oscillation

Maruyama, Taketo

doi:10.2151/jmsj1965.46.5_327

Cited by 53 publications

(58 citation statements)

References 9 publications

(9 reference statements)

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“…These longitudinal waves were identified with the Kelvin waves whose existence had also been predicted in Matsuno's theory (1966). Maruyama (1969) confirmed the existence of the 10-to 15-day period as well as of the 4-to 5-day period in the spectra of the 50-mb winds of Canton Island. Wallace and Change (1969) found that a 10-to 15-day periodicity is pronounced also in the lower tropospheric levels especially in the zonal component.…”

Section: Introductionsupporting

confidence: 67%

“…Maruyama (1967) and Lindzen and Matsuno (1968) identified the observed waves as mixed Rossbygravity waves which were obtained in the theory of equatorial waves (Rosenthal, 1965;Matuno, 1966;Lindzen, 1967). Further studies of Maruyama (1968 b) and Yanai and Hayashi (1969) established that these planetary-scale waves carry both westerly momentum and wave energy upward and the sensible heat poleward.…”

Section: Introductionmentioning

confidence: 88%

“…They identified this periodicity with Kelvin waves which must propagate eastward. Maruyama (1969) followed this interpretation based on the co-spectral study of u and v at Canton Island. On the other hand, Wallace and Chang (1969) related the long period zonal wind oscillation below the 500-mb level to some westward moving waves.…”

Section: Remarks On the Interpretation Of Spectrum Analysismentioning

confidence: 99%

“…The inter-level and inter-station cross spectrum analyses revealed that the peak in the upper troposphere and lower stratosphere was due to the passage of the planetaryscale waves found by Yanai and Maruyama (1966) which were intensively studied by Maruyama (1967Maruyama ( , 1968. The waves have a horizontal wavelength on the order of 10,000km and a large * Division of Meteorology , Contribution…”

Section: Introductionmentioning

confidence: 99%

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A Further Study of Tropical Wave Disturbances by the Use of Spectrum Analysis

Yanai

Murakami

1970

Journal of the Meteorological Society of Japan

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The upper wind data of the tropical Pacific stations during the period April through July 1962, which were previously studied by Yanai et al. (1968), are re-examined with respect to both the zonal and meridional wind components covering a wider spectral range from 2 to 25 day periods. A few new samples are added to study the wave disturbances in the western Pacific south of the equator.The results of the power spectrum analysis are presented in height-frequency diagrams. Besides the previously known 4-to 5-day periodicity of the meridional wind component, a pronounced zonal wind oscillation with periods longer than 10 days is found throughout the entire troposphere and the lower stratosphere at most of the stations. A periodicity near 7 days in the zonal component is isolated at some stations. All of the major spectral peaks show a maximum concentration of power density in the upper troposphere.Regional differences in the spectral density distribution in the height-frequency diagrams are examined. A preliminary consideration of the interpretation of the time series analysis is also made.

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Section: Introductionsupporting

confidence: 67%

Section: Introductionmentioning

confidence: 88%

Section: Remarks On the Interpretation Of Spectrum Analysismentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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A Further Study of Tropical Wave Disturbances by the Use of Spectrum Analysis

Yanai

Murakami

1970

Journal of the Meteorological Society of Japan

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“…Maruyama (1968a), using the data from Canton Island (2.8S, 171.7W) for the three year period from June 1957 to May 1960, presented a time sequence of the power spectra of the meridional wind component as it relate to the QBO. The sequence showed that the power density at a period of about 4 days increased when the absolute value of the mean wind speed decreased.…”

Section: Introductionmentioning

confidence: 99%

Annual and QBO-Synchronized Variations of Lower-Stratospheric Equatorial Wave Activity over Singapore during 1961-1989

Maruyama¹

1991

Journal of the Meteorological Society of Japan

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Annual and QBO-synchronized variations (variations synchronized with the QBO cycle of the zonal wind) of lower-stratospheric equatorial wave activity were investigated by spectrally analyzing the upper-air data at Singapore (1.4N, 104.OE) for the period January 1961 to February 1990. To measure the equatorial wave activity, the quadrature spectra between the zonal wind component and temperature integrated over the period range 7.4-32 days were used for Kelvin waves, and the power spectra of the meridional wind component integrated over the period range 3.3-5.1 days for mixed Rossby-gravity waves.Annual variations in the mixed Rossby-gravity wave activity were found at the 30, 50 and 70hPa levels with a maximum around March. The amplitude was largest at the 70hPa level. For the Kelvin wave, a weak annual variation was found at 70hPa. QBO-synchronized variations were found in the Kelvin wave activity at the 30, 50 and 70hPa levels. A QBO-synchronized variation of mixed Rossbygravity wave activity was found at 30hPa, but was unclear at the 50 and 70hPa levels. Annual variations of mixed Rossby-gravity wave activity in the 50-70hPa layer appear to be related to a rapid descent of the easterly wind regime during March-June and a slow descent in July-February during the layer 30-50hPa layer.

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On the variance spectra and spatial coherences of equatorial winds

Parker

1973

Quart J Royal Meteoro Soc

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The variance spectra of daily zonal and meridional winds in the troposphere and lower stratosphere over Gan (00°41′S, 73°09′E) were investigated. The total zonal variance considerably exceeded the total meridional variance at all the levels studied except the surface. In the upper troposphere the total zonal variance had a marked peak caused almost entirely by effects with periodicities greater than 10 days. The variance due to 4‐ to 5‐day meridional effects usually had a maximum slightly below the tropopause. However, at all the levels investigated this variance fluctuated considerably with time although without showing any long‐term regularities. Some specific 4‐day meridional motions at 150 mb over the equatorial regions between Gan and East Africa appeared to progress westward with a zonal wavelength of between 10,000 and 12,000 km. The vertical coherence of daily tropospheric winds over Gan was found to be weak on a scale of several km. Correlation coefficients between daily tropospheric winds over Gan and corresponding winds over Port Victoria (04°37′S, 55°27′E) were found to be small except for part of the upper troposphere.

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Time Sequence of Power Spectra of Disturbances in the Equatorial Lower Stratosphere in Relation to the Quasi-Biennial Oscillation

Cited by 53 publications

References 9 publications

A Further Study of Tropical Wave Disturbances by the Use of Spectrum Analysis

A Further Study of Tropical Wave Disturbances by the Use of Spectrum Analysis

Annual and QBO-Synchronized Variations of Lower-Stratospheric Equatorial Wave Activity over Singapore during 1961-1989

On the variance spectra and spatial coherences of equatorial winds

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