Island Climate Update 36 - September 2003

23 March 2007 - 2:21pm

Science Centres: Climate

September

Monthly climate

ENSO & SST

Forecast validation

Three-month outlook

Feature article

Data sources

Feature article
Information on Drought Stuart Burgess and Ashmita Gosai, NIWA Climate Applications and Research Group The issue of drought can be a major concern in some Southwest Pacific countries. Drought occurs during a sustained period of low rainfall, which has persisted long enough to produce serious hydrological imbalances.

Forecast validation
Forecast validation Forecast period: June to August 2003 Normal or above normal rainfall was expected from Papua New-Guinea east-southeast to the Society Islands of French Polynesia. Average or below normal rainfall was forecast for the Marquesas Islands. Near normal rainfall was expected elsewhere. Rainfall was below normal in an extensive region along the equator from west of the Caroline Islands to the region northeast of the Marquesas Islands, and also from the Coral Sea southeast to the region south of Tonga.

ENSO & SST
ENSO and Sea Surface Temperatures Neutral ENSO state in the tropical Pacific Ocean Weaker tradewinds in western equatorial Pacific The Equatorial Pacific atmosphere and ocean remains in a neutral state. The equatorial sea surface temperature (SST) anomalies are generally positive across the Pacific. The NINO3 SST anomaly weakened slightly to +0.3°C in August (from +0.4°C in July), and NINO4 is about +0.7°C. The three month (June – August) means were +0.1°C and +0.6°C for NINO3 and NINO4, respectively.

Monthly climate
Climate developments in August 2003 Extremely dry in New Caledonia and Vanuatu A large area of suppressed convection occurred from the Solomon Islands southward to include Vanuatu and New Caledonia, and eastward to encompass Western Kiribati, Rawaki, and Tokelau. Many sites in these areas recorded less than 25% of their normal August rainfall, especially Vanuatu and northern areas of New Caledonia where it was extremely dry and some gauges recorded totals below 10 mm.

Three-month outlook
Rainfall outlook for September to November 2003 Normal or above normal rainfall is expected in Papua New Guinea and the Austral Islands Normal or below normal rainfall in the equatorial region and Tuvalu, Fiji, and the Tuamotu and Marquesas Islands Neutral ENSO conditions suggest a near normal rainfall pattern over many countries in the region.

September
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 36 – 8 September 2003 August’s climate: A large area of suppressed convection occurred from the Solomon Islands southward to include Vanuatu and New Caledonia, and eastward to encompass Western Kiribati, Rawaki, and Tokelau.

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