Island Climate Update 41 - February 2004

The Southwest Pacific Climate in 2003
Stuart Burgess and Dr Jim Salinger, NIWA
The 2002/03 El Niño event, although decaying, had a significant impact in the Southwest Pacific. The event commenced in May 2002, had weakened by January 2003, and dissipated by April (Fig.1).This had a noticeable impact on the Southwest Pacific rainfall anomalies at the beginning of the year with above average rainfall over Eastern and Western Kiribati until it dissipated in April, and below average rainfall over much of New Caledonia and Fiji during the first few months of 2003.

Forecast validation
Forecast period: November 2003 to january 2004
Average or above average rainfall was expected in Papua New Guinea, the Solomon Islands, Samoa, and central French Polynesia. Below average rainfall was forecast for Eastern Kiribati and the Marquesas Islands, and average or below average rainfall from Vanuatu to Niue, including Fiji and Tonga.
Rainfall was lower than expected in Papua New Guinea, New Caledonia, and the Society Islands and higher than expected in Pitcairn Island and the Marquesas Islands, and as forecast elsewhere.

ENSO and Sea Surface Temperatures
The equatorial Pacific remains in a neutral state
Anomalous equatorial SSTs continue to ease
The equatorial Pacific remains in a neutral ENSO state. Anomalous equatorial SSTs continue to ease, but are still higher than normal, especially in the west. The mean SOI for January was -1.3, and -0.3 for November to January.

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 41 – 5 February 2004
January’s climate: The South Pacific Convergence Zone (SPCZ) was a major feature in January’s climate, being located much further north and east than usual, extending east from the region north of the Solomon Islands, toward the Marquesas Islands and Pitcairn Island.

Climate developments in January 2004
SPCZ much further north and east than usual
Extremely high rainfall from the Marquesas Islands to Pitcairn Island
Extremely low rainfall in many tropical islands about and west of the Date Line
The Southwest Pacific in January OLR and rainfall anomaly pattern was almost opposite to that of December. The SPCZ was located much further north and east than usual, extending east from the region north of the Solomon Islands, toward the Marquesas Islands, and down to Pitcairn Island.

Rainfall outlook for February to April 2004
Above average rainfall in Western Kiribati and the Solomon Islands
Average or below average rainfall likely over Eastern Kiribati and the Marquesas Islands
Near average rainfall elsewhere
Enhanced convection is expected in the equatorial region west of the Date Line, resulting in above average rainfall in Western Kiribati and the Solomon Islands.
Suppressed convection is expected in the eastern equatorial Pacific which is likely to result in average or below average rainfall over Eastern Kiribati and the Marquesas Islands.

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