Abstract
Vectors showing cloud movements observed by the geostationary meteorological satellite "Himawari" (0°, 140°E) were studied with the use of a spectral analysis for the period from May 1978 to December 1980. A large-scale upper tropospheric zonal wind oscillation with a period of 30-50 days was detected. Its amplitude is 3 m•s-1 on the average over the equator. The oscillation appeared to originate in the equatorial region and to behave like a standing oscillation with an antinode region near 110-120°E and a node region at 150-160°E or further eastern. The oscillation was found to be in an active stage from April 1979 to June 1980, and inactive stage prior to March 1979 and after July 1980.
