Planetary Pressure Wave of 4- to 5-Day Period in the Tropics

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  • 1 Indian Institute of Tropical Meteorology, Poona, India
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Abstract

Surface pressure data during the International Geophysical Year period for 76 stations in the tropical zone 20°N–20°S have been examined to investigate the propagation characteristics, if any, of the 4- to 5-day pressure oscillations. Cross-spectrum analysis with a first-difference filter and the Tukey window has been employed. The phase spectrum shows that the 4- to 5-day oscillations result from a westward moving wave having a periodicity of 4–5 days and wave number 1. The direction of propagation is identical in both hemispheres and shows no inclination to latitude circles.

Abstract

Surface pressure data during the International Geophysical Year period for 76 stations in the tropical zone 20°N–20°S have been examined to investigate the propagation characteristics, if any, of the 4- to 5-day pressure oscillations. Cross-spectrum analysis with a first-difference filter and the Tukey window has been employed. The phase spectrum shows that the 4- to 5-day oscillations result from a westward moving wave having a periodicity of 4–5 days and wave number 1. The direction of propagation is identical in both hemispheres and shows no inclination to latitude circles.

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