Chapter I Intro & Objectives - SPREP

PHOENIX ISLANDS PROTECTED AREA MANAGEMENT PLAN
Chapter III. Background, 1. Physical Setting of the Islands
Draft 1 March 2007
Quinn and Burt (1970) developed a method for predicting abnormally heavy rainfall in the
Pacific equatorial dry zone (including the Phoenix Islands). This was partially based on
Abrariringa (Canton) rainfall data. The method was 76 percent effective in predicting heavy
rainfall between 1 to 8 months in advance based on pressure changes over time.
Tuna and Billfish Assessment Programme (1993) provided 40 years of SOI in figure form
(see Figure III-1.34 below). When the SOI is positive, it is a La Niña event. When SOI is
negative, it is an El Niño events.
Figure III-1.34. Southern Oscillation Index (SOI), 1950 to 1990. Dots are actual
index values and lines are 5 month average. Positive values are
La Niña events, negative values are El Niño events.
(source: Tuna and Billfish Assessment Programme 1993).
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