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William L. Donn and Maurice Ewing


Atmospheric waves from the Soviet nuclear test of 30 October 1961 axe described for nine stations having wide global distribution. The records are characterized by waves which begin with the highest amplitudes and which show normal dispersion. These appear to be superimposed on a lower amplitude, long period train of waves which show inverse dispersion. As shown on dispersion curves of group velocity against period, a maximum of group velocity is indicated by the Airy phase formed through the merging of the two dispersive trains. A more prolonged train of waves of nearly uniform period is attributed to higher modes. The direct waves from the epicenter to the stations give dispersion curves that indicate significant variation in atmospheric structure along different azimuths and probably along different segments of the same azimuth. The curves for waves which have travelled more than once around the earth represent better sampling of world-wide atmospheric conditions and give better agreement with preliminary theoretical models. The average speed of the first arrivals is 324 m per sec, comparing well with the maximum obtained for the Krakatoa eruption.

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William Donn, Richard Rommer, Frank Press, and Maurice Ewing

Records from sensitive microbarovariographs installed at Palisades, N. Y., Columbia University in New York City, U. S. Merchant Marine Academy, Kings Point, L. I. have been studied in connection with synoptic and local weather data. A number of interesting pressure events have been noted in connection with the passage of certain synoptic situations, These include pressure pump lines, squall lines, cold fronts and thunderstorms. Low level turbulence or convection associated with certain air masses at certain times is well-recorded by short-period pressure variations. Conclusions regarding the origin of squall lines are drawn from the empirical evidence given.

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