Description of Global-Scale Circulation Cells in the Tropics with a 40–50 Day Period

Time Variation of Cloud Amount with about 30-days Period in the Western North Pacific Region

“…As noted by Krishnamurti and Subrahmanyam (1982), Julian (1971, 1972) and Yasunari (1981), the spectral analysis of wind time-series also exhibited considerable power in the range of 30 to 50 days. Julian (1971, 1972) described that the oscillation in various variables with a period range of 40 to 50 days was the result of an eastward movement of large-scale circulation cells oriented in the equatorial zonal plane. Julian and Madden (1981) point out that the oscillation in cloudiness described by Yasunari (1979Yasunari ( , 1980 would be a portion of the nearly global equatorial oscillation.…”

“…Specially the peak of about 30 days is interesting as showing a long period variation of cloudiness. As noted by Krishnamurti and Subrahmanyam (1982), Julian (1971, 1972) and Yasunari (1981), the spectral analysis of wind time-series also exhibited considerable power in the range of 30 to 50 days. Julian (1971, 1972) described that the oscillation in various variables with a period range of 40 to 50 days was the result of an eastward movement of large-scale circulation cells oriented in the equatorial zonal plane.…”

Unfolding the relation between global temperature and ENSO

“…This variability may arise from the Madden-Julian Oscillation (MJO) [Madden and Julian, 1972], which produces westerly wind events, which in turn can generate Kelvin waves as they propagate eastward [McPhaden, 1999]. Kelvin waves can also be generated by Rossby waves reflecting at the western boundary.…”

Interaction Between the Active-Break Cycle of the Summer Monsoon and the Circulation in Eurasia and the Western Pacific

“…1. The major break monsoon in Central India (defined here as more than 2 consecutive weeks with less than 40% of weekly normal rainfall) begin during July and August in 1965, 1966, 1968, 1972, 1974, and 1979. With a sole exceptions of July 1966, all the major break monsoon begin during high summer (defined here as a 50 day period from 15 July to 2 September).…”

“…The length of the active-break cycle have been shown to have the dominant periodicity of about 15 days (Krishnamurti and Bhalme, 1976;M. Murakami, 1976) and about 30 to 50 days (Madden andJulian, 1971, 1972). Yasunari (1979) has separated these two modes and shown that the major active-break cycle of the monsoon is associated with the 30 to 40 day mode.…”