Island Climate Update 30 - March 2003

23 March 2007 - 1:10pm

Science Centres: Pacific Rim

March

Monthly climate

ENSO & SST

Forecast validation

Three-month outlook

Feature article

Data sources

Feature article
The Southwest Pacific Climate in 2002 By Stuart Burgess, Ashmita Gosai, and Dr Jim Salinger, NIWA The year 2002 was one of more contrasts across the Southwest Pacific. Important drivers of the annual pattern were the development of the El Niño conditions during the second half of the year (See Fig.1), the decreased strength of the trade winds, and the distribution of warm sea surface temperature (SST) anomalies. Anomalous equatorial westerlies occurred about and west of the Dateline and in the central Pacific from July through November.

Forecast validation
Forecast validation Forecast period: December 2002 to February 2003 The El Niño related region of enhanced convection over Western and Eastern Kiribati was expected to persist. Above average or average rainfall was also expected in Tuvalu and Tokelau. A tendency towards below average rainfall was forecast for a broad region from the Solomon Islands southeast to the Southern Cook Islands, including Vanuatu, New Caledonia, Fiji, Tonga, and Niue, as well as the Marquesas Islands.

ENSO & SST
ENSO and Sea Surface Temperatures El Niño easing to neutral state Equatorial Pacific SSTs weaken further during February Based on the oceanic and atmospheric observations, the El Niño event is now easing back towards a neutral state. Most leading El Niño Southern Oscillation (ENSO) models indicate that the event will weaken to neutral state by end of May 2003. The NINO3 SST anomaly dropped 0.5°C in February (now +0.5°C), and NINO4 dropped to +1.0°C.

March
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 30 – 6 March 2003 February’s climate: The El Niño episode although weakening continued to affect Southwest Pacific rainfall patterns, with enhanced convection and above average rainfall extending from Western Kiribati through Tokelau to the Northern Cook Islands. In contrast, a large area of suppressed convection and below average rainfall extended from Papua New-Guinea to Niue.

Monthly climate
Climate developments in February 2003 SPCZ produces enhanced convection from Western Kiribati to Pitcairn Suppressed convection from Papua New-Guinea to Niue The SPCZ was generally displaced further north and east than average, with enhanced convection over much of the region from Western Kiribati southeast to Pitcairn Island. An equally large area of enhanced convection also occurred further west, over Indonesia and much of Australia.

Three-month outlook
Rainfall outlook for March to May 2003 Above average rainfall in Western and Eastern Kiribati, average or above average rainfall expected in Tuvalu Average or below average rainfall from New Caledonia east to Niue and parts of French Polynesia Below average rainfall in the Marquesas Islands Enhanced convection is expected to continue over Western and Eastern Kiribati resulting in above average rainfall.

Data sources
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