Interruptions in the Normal Westerly Flow of the General Circulation of the Atmosphere

Author: Smith, Theodore Beaton

Year: 1949

Degree: Dissertation (Ph.D.)

Advisor: Elliott, Robert Dunshee

Committee Member: Unknown, Unknown

Option: Meteorology; Aeronautics

DOI: 10.7907/s796-wx62

Abstract

Certain effects associated with the intrusion of stable, persistent high pressure cells into the normal westerly flow of the general circulation of the atmosphere are investigated. These intrusions are termed Blocking Action processes.

By means of empirical and semi-statistical procedures these processes are found to cause the development of long stable wave patterns in the atmosphere downstream from the point of inception. These wave patterns may exist for periods of a month or more. The wave length of these stationary long waves is found to be longer than that determined by other investigators. This is explained on the basis of the larger amplitude of the long waves associated with the Blocking Action process.

A theory of the formation of these blocking high cells is suggested based on the accumulation of heat in low latitudes and the necessity for the readjustment of the general circulation to redistribute this heat. One means of dissipation of the blocking cells is shown to be the formation of a wave pattern in the atmosphere which is out of phase with the stable wave pattern formed by the blocking High.

The optimum mean pressure chart is discussed in terms of the long period Blocking Action processes. The optimum length chart is found to cover a three day period or a period of greater than twenty days depending on the use to be made of the chart.

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