Island Climate Update 21 - June 2002

Figure 1. Phases of the Interdecadal Pacific Oscillation from 1950 to 2000.
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Figure 2. Trends in annual mean temperature (0.01°C) between the most recent positive and negative phase of the IPO.
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Figure 3.

Forecast validation
Forecast period: March to May 2002
Rainfall was expected to be above average in Niue, and average to above average from Fiji across to Tonga, and in Western Kiribati. Below average rainfall was forecast for the region north of about 12°S from Tokelau to the Marquesas, including Eastern Kiribati. Average rainfall was expected in the other parts of the region.
Rainfall was as expected for many of the forecast areas. However, it was higher than forecast in New Caledonia, Samoa and the Marquesas and Austral Islands.

ENSO and Sea Surface Temperatures
In the tropical Southwest Pacific, a band of much warmer than usual water at the surface (at least 1.0°C above average) extends from Kiribati south to affect the Solomon Islands, Fiji and Tuvalu. Surface waters at least 1.0°C above average also encompass the region to the south and west of Pitcairn Island.
Most of the Southwest Pacific is warmer than average ( 0.5–1.0°C).
Equatorial Pacific Ocean temperatures continued to warm through May with SSTs being 1.0°C warmer (US analysis, +1.0°C) immediately west of the date line.

An overview of the present climate in the tropical South Pacific Islands, with an outlook for the coming months, to assist in dissemination of climate information in the Pacific region.
Number 21 – 11 June 2002
May’s Climate: The South Pacific Convergence Zone (SPCZ) was further south than average west of the date line, but further north than usual over much of the region to the east.

Enhanced convection south of the Solomon Islands across to Fiji and from the Tokelaus to Pitcairn Island
Below average rainfall in the Southern Cooks and Society Islands
A large area of enhanced convection with areas of above average rainfall affected the region south of the Solomon Islands across Vanuatu to the north of Fiji, as the SPCZ continued to be displaced south of its mean position in that region.

Rainfall outlook for June to August 2002
Above average rainfall in equatorial latitudes from Nauru to Kiribati
Average to below average rainfall in Papua New Guinea, Fiji and the Marquesas and Austral Islands
Below average rainfall for New Caledonia and Samoa
Mainly average rainfall in other areas
In the Western Pacific, the South Pacific Convergence Zone (SPCZ) was further south of its normal position lying just north of Vanuatu and Fiji during May. It lay further northeast than average east of the date line, lying just north of the Cook Islands and over parts of French Polynesia.

Sources of South Pacific rainfall data
This bulletin is a multi-national project with important collaboration from the following Pacific nations:
American Samoa
Australia
Cook Islands
Fiji
French Polynesia
Kiribati
New Caledonia
New Zealand
Niue
Papua New Guinea
Pitcairn Island
Samoa
Solomon Islands
Tokelau
Tonga
Tuvalu
Vanuatu
Requests for Pacific island climate data should be directed to the Meteorological Services concerned.
Acknowledgements
This bulletin is made possible with financial support from the New Zealand Agency for International Development (NZAID), Wellington, New Zealand, wi