New Releases by Jonathan Thomas

An attempt has been made to identify tropical waves with periods less than 20 days in the Indian Ocean by spectrum analysis of radiosonde data for five stations, widely scattered over the Indian Ocean area. The data used is for the period from January to September, 1973, which was further divided into five-month seasons, overlapping in May due to consideration of the monsoonal shift in the mean flow. Three spectral peaks in the 10-17 day, 6-7 day and 4-5 day ranges have been detected. Cross-spectrum analysis reveals a basically in-phase structure in the vertical in the lower troposphere and reversed phase at upper levels. (Modified author abstract).