On tropical cyclone activity in the Southern Hemisphere: Trends and the ENSO connection

Abstract

A collective list of historical El Niño and La Niña events has been developed, based an examination of different indices describing the El Niño-Southern Oscillation (ENSO) phenomenon. Based on this list, tropical cyclone (TC) data from a newly created TC archive for the Southern Hemisphere (SH) have been stratified accordingly and significant changes in TC occurrences depending on warm or cold phases of ENSO have been identified. TC trends in the SH (area south of the equator, 30°E to 120°W) have been examined. For the 1981/82 to 2005/06 TC seasons, there are no apparent trends in the total numbers and cyclone days of TCs, nor in numbers and cyclone days of severe TCs with minimum central pressure of 970 hPa or lower. However, significant positive trends in occurrences and cyclone days of severe TCs with minimum central pressure of 945 hPa or lower have been identified. Copyright 2008 by the American Geophysical Union.