Crews fighting cold war for wind

SIMON COLLINS finds that when it comes to weather, Team New Zealand and Alinghi don't guess.

Both Team New Zealand and Alinghi will go to the starting line this weekend armed with the best weather forecasts money can buy.

Twenty years ago, when Team NZ weather boss Roger "Clouds" Badham worked on his first America's Cup assignment off Newport, Rhode Island, weather forecasting for each boat was a one-person job.

Today the Sydneysider commands a team of 10 plus part-timers on his fleet of seven weather boats stationed strategically around the course on race days.

There's also a network of land stations, including one on Motutapu Island shared with Alinghi and several earlier challengers. Alinghi and the home team also share a buoy in the racing area.

"If you put all the hardware together, it's not cheap," says Badham.

"I'm sure we have been a lot more lean than what they have been next-door - I hope we have - but you are talking all-told $1 million or more."

"It's a bit like the Cold War, you have to match your opposition," he says.

Team NZ started with just six forecasters and four weather boats. Badham's opposite number at Alinghi, Aucklander Jon Bilger, started with only two fulltimers and is now up to nine, plus seven weather boats.

"We've only just ramped up quite recently," Bilger says.

"Oracle, Prada and OneWorld all had much bigger teams for much longer periods of time. Oracle had eight or 10 people for two or three years.

"We saw how many boats Oracle and Prada had and we had to match it."

Georgina Griffiths, a yachtie at the National Institute of Water and Atmospheric Research (Niwa) who has consulted for several syndicates, says most teams have their own computerised weather model and can read off wind estimates almost metre by metre.

"They monitor it every minute. You haven't got much time before a 20-knot southwesterly has gone," she says.

"They are measuring the swings in the wind direction to try and give them a direction - is the lift on the left more than on the right?

"Maybe the weather at the end of the day is what wins it for you. If there's not much difference in the boats, then the call on the weather is going to become more and more important."

Especially in the Hauraki Gulf, where the weather is far more changeable than at Perth or San Diego. This is no straight, boring coast, but an intricate maze of headlands and islands with three distinct layers of intersecting weather patterns.

At the highest level is the standard mid-latitude pattern of high and low-pressure systems moving from west to east across New Zealand. They are part of a global system in which cold air moves from the poles to the equator in a constant but vain attempt to even out the temperature differences.

In northern New Zealand that means the predominant winds for most of the year are southwesterlies, funnelling especially though the low-lying Auckland isthmus between the hills of Northland in the north and the Coromandel in the south.

Occasionally, a tropical cyclone from the Pacific brings a particularly deep low-pressure system southwards. Griffiths says there's about a one in four chance that this will happen in February, possibly halting cup racing for a day or two.

More usually, however, the southwesterlies are at their weakest at this time of year. Instead, a second, regional weather pattern becomes more important in which air is heated and rises over land each day, sucking in afternoon sea breezes to fill the vacuum left near ground level.

As a result, February has roughly equal proportions of southwesterlies and northeasterlies in the gulf, both blowing in over the isthmus. A row of cloud often marks the front between these two breezes, usually over land but sometimes to the east or west depending on which breeze is stronger.

Finally, at the most local level, each piece of land has its own effects. Whichever way the wind is blowing, it is usually stronger in the little channel between the tip of the Whangaparaoa Peninsula and Tiritiri Matangi. And Rangitoto produces its own hot air.

"Rangi is a nice, red, scoria hot thing and sometimes you can see, on a really hot afternoon, Rangi is sucking in the wind," says Griffiths.

"The air above it rises, and it starts sucking the wind away from wherever it happens to be. Then there might be 'holes' of wind, it will put a dampener on the wind."

For the forecasters, all this must be predicted in advance. When each race day dawns, "Clouds" Badham and his lieutenant Chris Bedford will have been at their computers from 4.30am or 5am, ready to brief the sailors by 7.30am.

Then they're out on the their own boat feeding in data and updating their forecasts to the the racing crew up to precisely five minutes before the race starts.

At that point, the rule is that communication stops. Despite all the expensive weather wizardry, the race itself will still be run on the experience and judgment of a few human minds.

nzherald.co.nz/americascup

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