Climate Update 44 - February 2003

29 March 2007 - 2:15pm

Science Centres: Climate

February

Climate

River flows

Soil moisture

Three-month outlook

Checkpoint

Backgrounder

Backgrounder
Backgrounder Pacific ENSO signal The El Niño event has passed its peak and is now waning. Equatorial subsurface temperature anomalies have weakened east of the dateline and westerly zonal wind anomalies have reduced in horizontal extent to a region near the dateline.

Checkpoint
Outlook and outcome – November 2002 to January 2003 Rainfall was near normal or below normal in many areas of the country as expected, but in the west and south of the South Island it was drier than predicted. Air temperatures were expected to be near average for the North Island and the north of the South Island, and average or below average elsewhere. Temperatures were lower than expected over the North Island and were close to those predicted for the South Island. River flows were higher than predicted over most of the North Island and the north of the South Island.

February
Climate Update is a summary each month of New Zealand's climate, including soil moisture and river flows. February 2003 – Number 44 January’s climate: This month was drier than normal apart from northern North Island regions. January’s river flows: January streamflows mostly low. Soil moisture levels: North Island soils from Waikato south were very much drier than normal by the end of January. Three month outlook: Early autumn is expected to be influenced by enhanced antocyclone activity over the Tasman Sea. Checkpoint: How well are we doing with our predictions? Backgrou

Climate
New Zealand Climate Wet in some northern regions; dry elsewhere Rainfall was at least 150 % of average in Northland, Auckland, Coromandel, and western Bay of Plenty, and double average in eastern parts of Northland and Coromandel. Whitianga recorded its highest January rainfall since records began in 1991.

Three-month outlook
The outlook for February 2003 to April 2003 Early autumn is expected to be influenced by enhanced anticyclone activity over the Tasman Sea with episodes of stronger than normal southwesterly winds across New Zealand.

River flows
New Zealand River Flows January streamflows mostly low January flows were below normal in many areas. Only Northland, inland Bay of Plenty, and East Cape recorded high flows.

Soil moisture
Soil moisture North Island soils from Waikato south were much drier than normal by the end of January. The soil moisture deficit was particularly severe in eastern areas, Manawatu, and Horowhenua. Northern and eastern South Island regions also had severe soil moisture deficit. Significant rainfall during January improved the moisture levels in upper North Island soils. Soil moisture deficit in the pasture root zone at the end of January (right) compared with the deficit at the same time last year (centre) and the long term end of January average (left).