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R. Madden
and
C. Parsons

Abstract

A method for gridding scanning radiometer (SR) data is outlined in complete detail. This gridding method, coupled with a suggested display technique, enables one to produce a real-time quantitative display of APT service SR data with only minimal computer capability.

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R. Madden
and
W. Sadeh

Abstract

The standard error of yearly and seasonally time-averaged station pressure values is estimated directly from a 49-year time series. The results compare well with similar estimates inferred from the autocorrelation character of the pressure data. The effect of seasonal variability in the autocorrelation on this standard error is indicated and a possible implication for numerical climatic-change experiments proposed.

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R. Madden
and
P. Julian

Abstract

No abstract available.

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R. Madden
and
P. Jullan

Abstract

Cross spectra between long time series (5–10 years) of pressure data from 27 stations and that from Canton Island show peaks in the coherence squares near 5-day periods. Phase angles indicate that these peaks are manifestations of a westward propagating, zonal wavenumber 1 disturbance. Sea-level pressures and 500-mb heights recorded during the IGY are filtered in time and harmonically analyzed in space revealing the westward propagating 5-day waves. A composite wave based on the IGY sea-level pressure data suggests that the amplitude of the disturbance increases with increasing latitude. The observed characteristics of the 5-day pressure wave are shown to he not inconsistent with those of a planetary wave, or wave mode of the second class, theoretically predicted by Laplace's tidal equations.

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R. A. Madden

Abstract

Lag one-year autocorrelations and spectra for summer and winter seasons are estimated from 64-Year time series at 87 North American stations. Linear trends are first removed from the data to eliminate the effects of very long-period (longer than 64 years) variations. Summer season temperatures appear to have more year-to-year correlation and “redder” spectra than those of winter seasons. High correlations and red spectra are not necessarily found more frequently at near-ocean stations than at interior stations. Excepting variance near the quasi-biennial period, which is not judged because of its proximity to the folding frequency, no spectral “peaks” are found. Because of their differing autocorrelations and spectra it is concluded that evidence for potential long-range (more than two but less than 32 years) predictability is greater in summer than in winter, and that this is due, at least in part, to less natural variability or climatic noise in summer than in winter.

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Roland A. Madden
and
Paul R. Julian

Abstract

Observational aspects of the 40–50-day oscillation are reviewed. The oscillation is the result of large-scale circulation cells oriented in the equatorial plane that move eastward from at least the Indian Ocean to the central Pacific. Anomalies in zonal winds and the velocity potential in the upper troposphere often propagate the full circumference of the globe. Related, complex convective regions also show an eastward movement. There is a zonally symmetric component to the oscillation. It is manifest in changes in surface pressure and in the relative atmospheric angular momentum. The oscillation is an important factor in the timing of active and break phases of the Indian and Australian monsoons. It affects ocean waves, currents, and air-sea interaction. The oscillation was particularly active during the First GARP (Global Atmospheric Research Program) Global Experiment year, and some features that were evident during the Monsoon Experiment are described.

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R. A. Madden
and
F. E. Robitaille

Abstract

No abstract available.

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Roland A. Madden
and
Paul R. Julian

Abstract

Nearly ten years of daily rawinsonde data for Canton Island (3S, 172W) have been subjected to spectrum and cross-spectrum analysis. In the course of this analysis a very pronounced maximum was noted in the co-spectrum of the 850- and 150-mb zonal wind components in the frequency range 0.0245–0.0190 day−1 (41–53 days period). Application of a posteriori sampling theory resulted in a significance level of ∼6% (0.1% prior confidence level). This type of significance test is appropriate because no prior evidence or reason existed for expecting such a spectral feature. Subsequent analysis revealed the following structure of the oscillation. Peaks in the variance spectra of the zonal wind are strong in the low troposphere, are weak or non-existent in the 700–400 mb layer, and are strong again in the upper troposphere. No evidence of this feature could be found above 80 mb, or in any of the spectra of the meridional component. The spectrum of station pressure possesses a peak in this frequency range and the oscillation is in phase with the low tropospheric zonal wind oscillation, and out of phase with that in the upper troposphere. The tropospheric temperatures exhibit a similar peak and are highly coherent with the station pressure oscillation; positive station pressure anomalies are associated with negative temperature anomalies throughout the troposphere. Thus, the lower-middle troposphere appears to be a nodal surface with u and P oscillating in phase but 180° out of phase above and below this surface. Evidence for this phenomenon was found in shorter records at Kwajalein (9N, 168E) but not at Singapore (1N, 104E) or Balboa, Canal Zone (9N, 79w). We speculate that the oscillation is a large circulation cell oriented in zonal planes and centered in the mid-Pacific.

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R. A. Madden
and
F. E. Robitaille

Abstract

No abstract available.

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R. A. Madden
and
E. J. Zipser

Abstract

Analysis of serial rawinsonde observations over the Line Islands during March and April 1967 reveals a multi-layered wind structure, especially in the meridional component, which changes sign as many as eight times below 20 km. The layering is strongest above 14 and below 9 km, and is most marked near the equator. Very large vertical wind shears are observed, occurring most frequently near the tropopause. It is likely that the most extreme shears are accompanied by considerable turbulence and may, therefore, represent significant kinetic energy sinks. The layered winds above 14 and below 9 km may be associated with vertically propagating waves. The wind variations in the 9–14 km region appear to be linked to changes in position and intensity of circulation features in either hemisphere rather than with a regular progression of wave disturbances.

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