Time and Space Spectral Analyses of Southern Hemisphere Sea Level Pressure Variability

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Abstract
This study examines the time-space structure of the standard deviation of daily summer and winter mean sea level pressure over the Southern Hemisphere, as identified in 20 years of analyses generated by the Australian Bureau of Meteorology and two long simulations with a GCM. The unfiltered variability derived from the operational analyses generally display a deal of zonal symmetry, particularly during the summer period, with maxima in the midlatitudes. The percentage of the temporal variance which is explained by the bandpass and low-pass components is calculated; in January and July the percentage of the variance explained by the bandpass data is maximized between 30° and 60°S and assumes values of typically 25%. In general, the low-pass data account for more of the variance and tends to achieve its maxima in low and high latitudes. The greatest contribution to the low-frequency field comes from the planetary-scale waves, particularly at higher latitudes. The synoptic and small-scale waves are ... Abstract This study examines the time-space structure of the standard deviation of daily summer and winter mean sea level pressure over the Southern Hemisphere, as identified in 20 years of analyses generated by the Australian Bureau of Meteorology and two long simulations with a GCM. The unfiltered variability derived from the operational analyses generally display a deal of zonal symmetry, particularly during the summer period, with maxima in the midlatitudes. The percentage of the temporal variance which is explained by the bandpass and low-pass components is calculated; in January and July the percentage of the variance explained by the bandpass data is maximized between 30° and 60°S and assumes values of typically 25%. In general, the low-pass data account for more of the variance and tends to achieve its maxima in low and high latitudes. The greatest contribution to the low-frequency field comes from the planetary-scale waves, particularly at higher latitudes. The synoptic and small-scale waves are ...

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