Tropical cyclones are tropical storms that are characterised by a low pressure centre, strong winds, and thunderstorms that produce heavy rain. Tropical cyclones form over warm water (from which they derive their energy) and generally move poleward. The lifetime of a tropical cyclone is typically about a week. Tropical cyclones may cause storm surges due to the inverse barometer effect (local rise in sea level due to ‘sucking’ of air upwards from the surface). Storm surges, strong winds, and heavy rainfall may cause damage to islands.
Under the Climate Present and Past project, NIWA undertakes research about tropical cyclones in the following areas: