Feb 12, 2014

A 66‐year tropical cyclone record for south‐east Africa: temporal trends in a global context

by
Jennifer M. Fitchett, Stefan W. Grab
,
International Journal of Climatology
  • Investigates changes in the frequency and timing of tropical cyclone landfalls over the south‐west Indian Ocean during the last 66 years
  • States that little is known about the spatial and temporal trends of such storm landfalls during recent historical times, specifically the last ca. 100 years
  • Analyzes three storm track records spanning periods of 66–161 years
  • Establishes that much of the perceived change in storm numbers can be attributed to improvements in storm detection methods over the past century
  • Finds no statistically significant trends in the frequency of tropical cyclone landfalls over Madagascar and Mozambique over the past 6 decades, despite more comprehensive records during the most recent period
  • States, however, that there is considerable interannual variability in the number of storms making landfall over the countries investigated; most probably driven by cyclical atmospheric forcing, including El Niño‐Southern Oscillation (ENSO) and the Quasi‐Biennial Oscillation (QBO)
  • Concludes that recent trends indicate an increasing number of tropical cyclones tracking to the south of Madagascar, potentially associated with the southward shift of the 26 °C isotherm, combined with a decrease in the steering flow during La Niña years