Short-Period Atmospheric Gravity Waves: A Study of Their Dynamic and Synoptic Features

Atmospheric gravity wave records at Palisades, N.Y., during the two-month period Nov.-Dec. 1969, are investigated in the light of concurrent weather patterns and atmospheric soundings. Although it seems to be a characteristic of atmospheric gravity waves that no one mechanism affords a complete explanation for their behavior, it is shown that many of the waves seem to be generated by shear instability of the upper tropospheric winds and that the pressure amplitudes of the waves are increased by the presence of large static stability in the lower troposphere. A simple, three-layer model is able to simulate these features. The synoptic applications of these observations are investigated, and it is shown that times of large-amplitude gravity waves often precede the onset of cyclonic precipitation by 12-24 hr, whereas times of small-amplitude gravity waves usually indicate continuation of fair weather.