Feature article

Climate Explorer

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Improving irrigation water use efficiency with probabilistic rainfall forecasts

Climate Explorer provides farmers and other irrigation managers a way of ensuring that irrigators are running only when they are needed. The web site provides daily updates of probabilistic forecasts of rainfall over the next 15 days for over 100 representative sites around New Zealand.

The forecasts are created by 'down scaling' southwest Pacific atmospheric conditions to New Zealand locations, combining outlooks from the latest international models with the history of weather conditions at each location. The objective of the forecasts is to show how expected synoptic conditions over the next few days are likely to change the background or climatological probability of the rain happening. Hence the forecasts are not categorical ('32 mm will fall tomorrow') but based on tendency ('under these conditions, it is much more likely to rain tomorrow than normal').

In all, five different measures of rainfall are forecast, including the examples for Timaru Airport shown below. In each case, the red line shows the climatological values, and the dark line and shaded band the mean and spread of model output respectively.

For more information, and to obtain an annual subscription for access to all regularly updated products, please contact [email protected].

Annual subscriptions: Individual $185+gst, Corporate $370+gst.

Take advantage of our 3-month free trial subscription offer, contact:
Andrew Tait, [email protected]