Island Climate Update 70 - July 2006

The Pacific Convergence Zones: 2005 and early 2006
A B Mullan, NIWA
Figure 1: Average rainfall rate (mm/day) from TRMM 0.25 degree analysis for months of February (upper) and September (lower) 2005. Contours at uneven of 0.5, 1, 2, 4, 6, 8, 10, 15, and 20 mm/day.
Figure 2: Average rainfall rate (mm/day) for April 2006.

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 70 – July 2006
June’s climate
South Pacific Convergence Zone (SPCZ) active over Papua New Guinea and the Solomon Islands
High rainfall occurred in central and southern Tonga and Niue
Low rainfall throughout New Caledonia
Temperature: below average in New Caledonia and northern Tonga; above average in French Polynesia
El Niño/Southern Oscillation (ENSO) and seasonal rainfall forecast

Climate developments in June 2006
Outgoing Long-wave Radiation anomalies for June 2006. (Click for enlargement and detail)
During June, the SPCZ was displaced further north and west than average, with enhanced convection extending from Papua New Guinea east over the Solomon Islands and the seas north of Vanuatu. The SPCZ was rather inactive to the east of the Date Line. Enhanced convection also occurred southeast of the Southern Cook Islands.

Tropical rainfall outlook: July to September 2006
Rainfall outlook map for July to September 2006. (Click for enlargement)
An extensive region of enhanced convection is expected from Papua New Guinea southeast to Pitcairn Island, including the Solomon Islands, Vanuatu, Wallis and Futuna, Fiji, Tonga, Niue, the Southern Cook Islands, and the Society, Austral, and Tumotu Islands.
Suppressed convection is expected over Tuvalu and the Marquesas Islands, where rainfall is likely to be below average.

Tropical pacific rainfall - June 2006
Territory and station name
June 2006 rainfall
total (mm)
June 2006 percent
of average
Australia
Cairns Airport
93.0
194
Townsville Airport
10.2
51
Brisbane Airport
59.4
84
Sydney Airport
186.4
148
Cook Islands
Rarotonga Airport
62.9
56
Penrhyn
88.4
62
Fiji
Rotuma
400.4
174
Udu Point
120.5
104
Nadi
39.9
61
Nausori
94.6
63
Ono-I-Lau
260.3
296
French Polynesia
Bora Bora Motu
94.4
103
Tahiti – Faa’a
97.8
153
Tuamotu, Takaroa
29.4
33
Gambier, Rikitea
110.4
68
Tubuai
142.8
123
Rapa
234.2

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