Climate Update 42 - December 2002

28 March 2007 - 11:17am

Science Centres: Climate

December

Climate

River flows

Soil moisture

Three-month outlook

Checkpoint

Backgrounder

Backgrounder
Backgrounder Pacific ENSO signal The orange-yellow shading along the equator, stretching west from Ecuador, is a typical 'footprint' of the El Niño phase of the El Niño -Southern Oscillation. The shading indicates that sea surface temperatures in the area are 1-2 °C or more above normal.

Checkpoint
Outlook and outcome – September to November 2002 Rainfall was lower than expected in the north and east of the North Island, and in Marlborough and parts of north and east Otago.

December
Climate Update is a summary each month of New Zealand's climate, including soil moisture and river flows. December 2002 – Number 42 November’s climate: November cold and windy: Dry and cold weather, and near normal river flows, in many areas. November’s river flows: November flows mostly near normal. Soil moisture levels: East coast soils were generally drier than normal by the end of October. Three month outlook: Cooler than normal in some places; drier than normal in the east. Checkpoint: How well are we doing with our predictions? Backgrounder: Rainfall observation net

Climate
New Zealand Climate Cold, windy November Cold and windy, and relatively dry in many places, November conditions overall were generally uncharacteristic of spring. Air temperatures were more than 2.0 °C below normal in central and northern parts of the North Island, and in parts of central and eastern Otago.

Three-month outlook
The outlook for December 2002 to February 2003 The present moderate El Niño event in the tropical Pacific is expected to last through summer, but should remain weaker than the 1997-98 event.

River flows
New Zealand River Flows November flows mostly near normal November streamflows were low in the north and northeast of the North Island, Nelson, coastal Marlborough, and South Canterbury. Flows were near normal elsewhere, except for some above average flows in north Canterbury.

Soil moisture
Soil moisture At the end of November, soil moisture levels were lower than normal in much of Northland, and in parts of Bay of Plenty, Hawke’s Bay, Manawatu, Marlborough, and Otago. Soil moisture deficit in the pasture root zone at the end of November (right) compared with the deficit at the same time last year (centre) and the long term end of November average (left). The analysis is done for an average soil type where the available water capacity is taken to be 150 mm.