Monthly climate

Climate developments in July 2005

The South Pacific Convergence Zone (SPCZ) extended from Papua New-Guinea to Tuvalu (associated with areas of enhanced convection, especially near Papua New Guinea). North of the Equator, the Inter-tropical Convergence Zone (ITCZ) extended eastward from the region south of the Marshall Islands. Overall outgoing long-wave radiation (OLR) anomalies were rather weak, and there were no large areas of suppressed convection.

Rainfall was more than 200% of average in parts of Queensland (Australia), Fiji, and the Southern Cook Islands, and at least 125% of average in parts of Western and Eastern Kiribati, southern Vanuatu, southern Tonga, Niue, central French Polynesia, and northern New Zealand. Rainfall was less than 50% of average in northern Tonga, the Norfolk and Kermadec Islands, and less than 75% of average in parts of southern French Polynesia.

Mean air temperatures were about 1.0 °C above average in Western Kiribati and northern and central French Polynesia, and about 0.5 °C about average in Tuvalu. In contrast they were about 1.0 °C below average in Fiji, and 0.5 °C below average in Vanuatu.

Tropical Southwest Pacific mean sea-level pressures were above average at 30° latitude over Australia, the north Tasman Sea, and further east toward the Date Line. Pressures were below average over along the Equator, east of Western Kiribati.

Along the Equator, surface equatorial easterlies occurred in 78% of observations at Tarawa, westerlies being infrequent.

Climate extremes in July 2005

Outgoing Long-wave Radiation (OLR) anomalies, in Wm-2. The July 2005 position of the SPCZ, as identified from total rainfall, is indicated by the solid green line. The average position of the SPCZ is identifi ed by the dashed green line (blue equals high rainfall and yellow equals low rainfall). The July position of the ITCZ is indicated by the solid blue line.