T El Nino/Southern Oscillation phenomenon (ENSO, for short) is the strongest source of natural variability in Earth's climate system. ' Although ENSO originates in the tropical latitudes of the Pacific Ocean, its climatic impact is felt globally. Variations in major rainfall systems that are attributed to ENSO range from droughts in Indonesia and Australia to storms and flooding in Ecuador and ...

Three previously published proxy records of El Nino/Southern Oscillation (ENSO) variability were compared: a documentary record from coastal South America; an ice-core record from the Quelccaya ice cap in Peru; and a tree-ring record record from arid site conifers in the southwestern United States. The records were calibrated with long ENSO instrument records, and all the proxy records showed s...

Recent advances in observational and theoretical studies of El Nino have shed light on controversies concerning the possible effect of global warming on this phenomenon over the past few decades and in the future. El Nino is now understood to be one phase of a natural mode of oscillation-La Nina is the complementary phase-that results from unstable interactions between the tropical Pacific Ocea...

The Northern Indian Ocean is unique in the global ocean because of seasonal reversal of winds as well as surface ocean currents. In the southern part of the Indian Ocean, a significant ocean-atmospheric phenomenon developed just like an El Nino phenomenon noticed in the Pacific Ocean. This phenomenon is known as the Indian Ocean Dipole. In this study we investigate the relationship between IOD ...

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This study explains why a number of El Nino properties (period, amplitude, structure, and propagation) have changed in a coherent manner since the late 1970s and why these changes had almost concurred with the Pacific decadal climate shift. Evidence is presented to show that from the pre-shift (1961–1975) to the postshift (1981–1995) epoch, significant changes in the tropical Pacific are found ...

Radiocarbon (14C) content of surface waters inferred from a coral record from the Galapagos Islands increased abruptly during the upwelling season (July through September) after the El Nino event of 1976. Sea-surface temperatures (SSTs) associated with the upwelling season also shifted after 1976. The synchroneity of the shift in both 14C and SST implies that the vertical thermal structure of t...

Coastal hurricanes create tremendous environmental change and generate huge financial losses. The relative infrequency of severe coastal hurricanes implies that empirical probability estimates of the next big catastrophe will be unreliable. Here we model hurricane activity and resulting insured losses using extreme value theory and Bayesian models. The occurrence of a hurricane above a specifie...

The size of the 300 mbar north circumpolar vortex, and its eastern, western, date line, and Greenwich hemisphere components, is estimated for the period 1963–2000 by planimetering the area poleward of 300 mbar contours in the main belt of westerlies on the mean-monthly polar stereographic analyses of the Institute of Meteorology of the Free University of Berlin. On the basis of the superposed e...

The objective of this study is to quantify the nature of the mechanisms of southern Africa rainfall variability, unrelated to the El Nino Southern Oscillation, by means of a simple empirical composite analysis, as a baseline for a more detailed study.