Island Climate Update 19 - April 2002

23 March 2007 - 12:15pm

Science Centres: Pacific Rim

April

Monthly climate

ENSO & SST

Forecast validation

Three-month outlook

Feature article

Data sources

April
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 19 – 10 April 2002 March’s Climate: An extensive area of enhanced convection occurred over equatorial waters about and west of the date line, from Papua-New Guinea to Western Kiribati, with another convective band associated with a southward displacement of the South Pacific Convergence Zone (SPCZ) extending from the northern Coral Sea southeast to affect Vanuatu and New Caledonia.

Feature article
Tropical cyclones Summary of the year 2001/02 tropical cyclone season The number of Southwest Pacific tropical cyclones 2001/02 season compared to frequencies during the past 20 years - Click to enlarge Southwest Pacific tropical cyclone tracks: November 2001 through 31 March 2002 - Click to enlarge Five tropical cyclones have occurred so far this season, which is the same number as for the whole of last season and well below average (see graph below).

Forecast validation
Forecast validation Forecast period: January to March 2002 The SPCZ was expected to be more active than usual and also further north than average of its normal location. Rainfall was expected to be average to above average in equatorial latitudes from Western Kiribati southeast to Tonga and Niue, including Tuvalu, Wallis and Futuna, and Samoa.Average to below average rainfall was expected in Vanuatu, Eastern Kiribati, the Society Islands, and the Southern Cooks, with below average rainfall in the Marquesas.

ENSO & SST
ENSO and Sea Surface TEmperatures Conditions are set for the development of an El Niño Warmer than average seas across the whole of the tropical Southwest Pacific The likelihood of an El Niño developing this year, based on recent observations in the equatorial Pacific, has increased. The equatorial Pacific Ocean temperatures are becoming warmer than average especially near South America where anomalies now exceed +1.0°C, The Southern Oscillation Index showed a substantial fall (to -0.8) in March, from weakly positive values over the previous two months.

Monthly climate
Climate developments in March 2002 Active convection over equatorial waters about and west of the date line High rainfall in parts of New Caledonia and southern French Polynesia Low rainfall from Tuvalu to northern French Polynesia An extensive area of enhanced convection occurred over equatorial waters about and west of the date line, from Papua-New Guinea to Western Kiribati, with another convective band associated with a southward displacement of the SPCZ extending from the northern Coral Sea southeast to affect Vanuatu and New Caledonia.

Three-month outlook
Rainfall outlook for April to June 2002 Above average rainfall in Kiribati and Vanuatu Average to below average rainfall from the Solomon Islands to the Marquesas, including the Northern Cook Islands and central French Polynesia The South Pacific Convergence Zone moved south in March, lying over Fiji, Tonga and the Southern Cook Islands: displaced further to the southwest than usual in areas west of the dateline. Rainfall is projected to be above average in Western and Eastern Kiribati and Vanuatu, and average to above average in New Caledonia, Fiji, Niue and Pitcairn Island.

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