Rain cumecs.

[sw_windbow]

Driving around in the rain today thinking wouldn't it be interesting for someone to come up with a total for an entire rain event like the new years rain just leaving.

For example, lets say 500 mm fell over a 30,000 square kilometre block of the Alps from Doubtful Sound to Greymouth. In 48 hours. Thats 5000 cubic metres per hectare, 500,000 m3 per km2, 1.5X10 m3 for the 30,000 km2 block. 312 million tonnes per hour. 5.2 million tonnes per minute. 86,800 cumecs!

With enough rain gauges, an automatic system could calculate the entire dump of each event. We could then see on the evening weather Jim Hickey saying, "West Coasters will be needing an extra set of gills after the rain they've had - 15 billion tonnes over the last 48 hours, thats 15 cubic kilometres!"

Even better, a system thats knows all about grass growth rates, soil moisture, would work out the economic value to agriculture of each event. For example: Southland got 50mm over 48 hours, leading to 20% increase in grass growth over next two weeks (relative to previous two weeks) increasing milk production by 8% over three week period beginning in one weeks time, boosting Southland dairy income by $15 million (( above what it would be with no rain( or $5 million above what it would be with average rain)) meaning rain's economic impact was a max of $86.80 per second over Southland. These are called dolsecs.

[Orion]

What a neat idea!

[TonyT]

You can integrate the rainfall rate output of the radars. Its done overseas.