Teleconnections of rainfall anomalies in the tropics and subtropics

Publisher Website
Google Scholar
Abstract
Statistical relations between the monthly rainfall amounts for 290 stations in the tropics and subtropics (30°S to 35 °N) are investigated by means of autocorrelation, power-spectrum, band-pass-fllter, cross-correlation, cross-spectrum, and coherence analyses with respect to space and time. The main point of interest is the regional distribution of lagged serial correlation coefficients in India and in Africa and the teleconnections and phase relationships of long-term fluctuations between stations in the equatorial Pacific, Indonesia, India, Africa and South America. Introduction One of the most striking climatic variations in recent years occurred in 1972. Drought conditions were prevalent not only across Africa and northern India, but also in South America and Australia. The severe deficiency of rainfall in the subtropics was compensated by excessive rainfall closer to the Equator in southern India, the Phillippines, the western Pacific and in the highlands of southern Africa. A preliminary survey by Flohn (1974) suggested that the occurrence of such anomalies in different parts of the tropics at almost the same time is not a particularly rare event. This investigation centres on the question of whether droughts in the tropics and subtropics occur simultaneously, randomly or mutually exclusively. How dominant are quasi-periodic processes with periods of more than one year, and what kind of spatial and temporal coherence exists in the tropics and subtropics? Observations The statistical calculations are based on long series of monthly rainfall measurements carried out over periods ranging from 66 to 135 years.

This publication has 0 references indexed in Scilit: