An investigation of ENSO's impacts in relation to formation and landfall of tropical cyclones in the eastern Pacific basin (from
western Mexican coast to the dateline) is presented. Statistical comparisons of hurricane frequency and landfall occurences were made between warm and cold ENSO phases with respect to the neutral or normal conditions. By using key characteristics of seasonal hurricane
distributions, the difference between the means of the respective hurricane populations is determined. Because the number of hurricane occurrences during an ENSO year is considered to be a discrete random event, sampled over time, a Poission distribution is assumed.
Data were obtained from the National Hurricane Center's "best track" dataset. This dataset contains track information from 1949 to the present. Several aspects of the tropical cyclone data were examined (ie. tropical cyclones, hurricane only, landfalling tropical cyclones, and landfalling hurricanes).
Results indicate that El Nino (warm phase) does not significantly increase the number of storms but does seem to be related to the number of landfalling storm events. There appears to be a stronger association between cold events and a decreased frequency of eastern Pacific cyclones with respect to "normal" conditions.