Island Climate Update 34 - July 2003

23 March 2007 - 2:20pm

Science Centres: Climate

July

Monthly climate

ENSO & SST

Forecast validation

Three-month outlook

Feature article

Data sources

Feature article
Climate Research Is there a role for indigenous knowledge in improving scientific understanding of future change in climate? Penehuro F Lefale, NIWA Damage from Tropical Cyclone Val, Samoa in 1991 Long before the advent of complex numerical climate models, indigenous communities have used changes in their environments to predict changes in the climate and weather. Social and communal activities like feasting and fishing were planned in response to these changes (below table).

Forecast validation
Forecast validation Forecast period: April to June 2003 Enhanced convection was expected over Western and Eastern Kiribati, possibly extending south to include the Solomon Islands, Tokelau and Samoa. Below average rainfall was expected in the Marquesas Islands of northern French Polynesia, with average or below average rainfall in New Caledonia and Fiji. Near average rainfall was projected elsewhere. Rainfall was above average in Vanuatu and from Tuvalu to the Society and Tuamotu Islands of French Polynesia, including Samoa.

ENSO & SST
ENSO and Sea Surface Temperatures Neutral conditions continue to prevail in the tropical Pacific Continuing negative SST anomalies along the South American coast During June, the tropical Pacific did not continue the trend towards La Niña conditions seen in May. Current ocean and atmospheric indicators are inconsistent with the phase of El Niño-Southern Oscillation (ENSO) being still unclear. The NINO3 SST anomaly was -0.4°C in June. However NINO4 rose to +0.5°C.

July
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 34 – 9 July 2003 June’s climate: The South Pacific Convergence Zone (SPCZ) was displaced further south than average east of the Date Line. As a result enhanced convection and extremely high rainfall was recorded over parts of French Polynesia during the month.

Monthly climate
Climate developments in June 2003 SPCZ active with extremely high rainfall over French Polynesia Reduced convection persists along the equator Record low rainfall in parts of Tonga and Niue The SPCZ was displaced further south than average east of the Date Line. As a result enhanced convection occurred over much of French Polynesia and at least 200% of average rainfall throughout much of the Society and northern Austral Islands.

Three-month outlook
Rainfall outlook for June to August 2003 Average or above average rainfall is expected from Papua New Guinea to the Solomon Islands Average or below average rainfall in Western and Eastern Kiribati Recent oceanic and atmospheric changes in the equatorial region suggest that July to September rainfall is likely to be average or above average from Papua New Guinea to Samoa including Tuvalu, Wallis and Futuna and Tokelau. The cooling of SSTs in the equatorial region just east of the Date Line is likely to result in average or below average rainfall in both Western and Eastern Kiribati over the

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