Statistical Analysis and Wavenumber-Frequency Spectra of the 500 mb Geopotential along 50°S

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  • 1 Institut für Meteorologie, Freie Universität Berlin, D-1000 Berlin 33, W-Germany
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Abstract

Daily 500 mb geopotentials gridded along 50°S are statistically analyzed for five summer and winter seasons (1959–64): 1) to establish climatic statistics of the macro-turbulent processes in the Southern Hemisphere westwind zone, and 2) to obtain a zonally averaged spectral description of the space-time (wave-number-frequency) structure of midlatitude disturbances of the Southern Hemisphere. In contrast to the Northern Hemisphere, two (instead of three) separated variance maxima are observed in the wavenumber-frequency spectra of the meridional component which contribute to transient eddy variance. They occur in the long (k=4–5,p=6–12 days, c≈ 6 m s−1) and short (k=6–7,p<6 days, c≈ 11 m s−1) period range of eastward traveling waves.

Abstract

Daily 500 mb geopotentials gridded along 50°S are statistically analyzed for five summer and winter seasons (1959–64): 1) to establish climatic statistics of the macro-turbulent processes in the Southern Hemisphere westwind zone, and 2) to obtain a zonally averaged spectral description of the space-time (wave-number-frequency) structure of midlatitude disturbances of the Southern Hemisphere. In contrast to the Northern Hemisphere, two (instead of three) separated variance maxima are observed in the wavenumber-frequency spectra of the meridional component which contribute to transient eddy variance. They occur in the long (k=4–5,p=6–12 days, c≈ 6 m s−1) and short (k=6–7,p<6 days, c≈ 11 m s−1) period range of eastward traveling waves.

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