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Island Climate Update 70 - July 2006

July

Monthly climate

Three-month outlook

Tropical Pacific rainfall

Feature article

Data sources

Feature article

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.

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 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

Monthly climate

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.

Three-month outlook

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

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

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

Taking a sediment sample. [Malcolm Green]