Chapter I Intro & Objectives - SPREP

PHOENIX ISLANDS PROTECTED AREA MANAGEMENT PLAN
Chapter III. Background, 1. Physical Setting of the Islands
Draft 1 March 2007
Humidity ranged from 64 to 80 percent (McIntire 1960).
Garnett (1983) reported that air temperature reached 31 0 C and dropped to 25 0 C at night.
Relative humidity was about 75 percent.
Storms - Lighting and thunder on Abariringa (Canton) were rare (Degener and Gillaspy
1955). Hurricanes were unknown.
McIntire (1960) noted that typhoons were unknown on Abariringa (Canton). Thunder and
lightning storms were also rare.
According to McIntire (1960), most days were partly cloudy (202 days a year), some days
were cloudy (87 days a year), while only 76 days were clear.
Garnett (1983a) reported that lightening and thunder were rare on Abariringa (Canton) and
cyclones were unknown.
Air Quality - There was periodically a haze caused by salt particles cast into the air by waves
breaking on the reef (Degener and Gillaspy 1955). This was termed, “ehukai” in Hawaiian.
This periodically caused difficulties to air operations.
Solar Radiation – Quinn and Burt (1968) reported that incoming solar radiation over the
tropical Pacific was much larger than previously thought. This was based on solar radiation
readings on Wake and Abariringa (Canton). Abariringa (Canton) had recorded average solar
radiation of 218 kLangleys based on 12 years of records. Even during rainy years,
Abariringa (Canton) received 195 kLangleys. Even with a 43 percent increase in annual sky
cover, there was only an 11 percent decrease in solar radiation for Abariringa (Canton).
ENSO - Morris (1975) analyzed the sequence of meteorological events on Abariringa
(Canton) during the 1972-1973 El Niño cycle. There was a strong correlation of heavy
rainfall with positive sea surface temperature anomaly and positive sea surface minus air
temperature difference (see Figure III-1.41 below). This did not indicate a causative
relationship. During rainy periods, easterlies were weak, or became westerlies. The
temperature in the upper troposphere was significantly warmer during El Niño months than
during dry periods.
Figure III-1.41. (a) Central Pacific rainfall in mm (12 month mean 1949 to 1969);
(b) sea surface temperature anomalies 5°N-5°S, 80°W-180°W
(12 month mean 1949 to 1969) (source: Morris 1975).
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