Island Climate Update 77 - February 2007

The Southwest Pacific climate in 2006
Stuart Burgess and Dr Jim Salinger, NIWA
Figure 1. The Southern Oscillation Index (SOI). (Click for enlargement)
Figure 2: Sea Surface temperature (SST) anomalies (departure from average,°C).(Click for enlargement)
Figure 3. Outgoing Long-wave Radiation (OLR) anomalies (departure from average).(Click for enlargement)
This year saw a change from a La Niña to an El Niño climate pattern in the Pacific. The first quarter of the year was dominated by weak La Niña-like (cold episode) characteristics, followed by a neutral period.

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 77 – February 2007
January’s climate
South Pacific Convergence Zone (SPCZ) further north and east than normal, with enhanced convection north of the Solomon Islands, southeast to Central French Polynesia; wet in Western Kiribati, and Central and Southern French Polynesia
Suppressed convection with low rainfall over Niue, Tonga, and the Coral Sea
Warmer than normal throughout Tonga and Fre

Climate developments in January 2007
Outgoing Long-wave Radiation anomalies for January 2007. (Click for enlargement and detail)
The South Pacific Convergence Zone (SPCZ) was located further north and east of its normal location in January, which is characteristic during an El Niño. Enhanced convection occurred extending from the region north of the Solomon Islands, southeast to Central French Polynesia, including Nauru, Tokelau, and the Northern Cook Islands. The Inter-Tropical Convergence Zone (ITCZ) continued to be more active than normal north of the Equator.

Tropical rainfall outlook: February to April 2007
Rainfall outlook map for February to April 2007.

Tropical cyclones
Two named tropical cyclones occurred in the Southwest Pacific in January, being Zita from the 23rd-24th *, and Arthur from the 24th-26th. This brings the total to four so far this season, for the region east of 150°E.Tropical cyclone Zita’s estimated maximum sustained wind speeds reached 50 knots on the 23rd near the Austral Islands, with damage reported in some areas. Arthurs’s estimated maximum sustained wind speeds reached 65 knots on the 25th between the Southern Cook Islands and Central French Polynesia.

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 produced by NIWA and made possible with financial support from the New Zealand Agency for International Development (NZAID), with a