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Could the Australian BOM get it more wrong?

Posted By Joanne Nova On December 23, 2010 @ 1:56 am In Global Warming | Comments Disabled

Warwick Hughes has spotted a neat trifecta: whether it be rain, maximums or minimums, the  BOM gets it wrong.

For this spring the Australian BOM predicted it would be dry and warm, instead we got very wet and quite cold.  The models are so bad on a regional basis, it’s uncannily like they are almost useful… if they call things “dry”, expect “wet”.

On August 24 the Australian BOM had pretty much no idea that any unusual wetness was headed their way. Toss a coin, 50:50, yes or no. Spring 2010 was going to be “average”, except in SW Western Australia where they claimed “a wetter than normal spring is favoured.” What follows were 100 year floods, or at least above average rain to nearly every part of the nation bar the part that was supposed to be getting more rainfall. In the chart below, all shades of “blue” got above average rainfall. The dark blue? That’s the highest rainfall on record.

The rainfall deciles chart original is here.

Australian Rainfall in Spring 2010 predictions vs reality BOM

http://jonova.s3.amazonaws.com/graphs/australia/australian-rainfall-spring-2010.gif

On August 24 the BOM predicted that spring would be “hot across the north”. Instead it was cold everywhere except in the west of WA.

BOM predicted max temperatures versus min temperatures

Australian Spring Maximum temperatures

Warwick Hughes linked to this unusually candid report of BOM seasonal rain forecasts (Vizard 2005).

“The results indicate that the forecasting system had low skill.”

They go on to explain just how low:

“Brier Skill Score and the receiver operating characteristic values were uniformly close to the no skill value.”

No skill value? How much is that “no skill” worth?

“The value of the forecasts for decision-makers was estimated using value score curves, calculated for six forecast scenarios. All curves indicated that no economic benefit could have been reliably derived by users of the seasonal rainfall forecasts, with the exception of users with decisions triggered by a small shift in the forecast from climatology, in which case small economic gains may have occurred.”

Now after all the advances in computer modeling the BOM show that Vizard is still right. Don’t get me wrong, it’s a tough job to predict the weather a few months out, and I’m not volunteering to try to do it. But then I’m not asking for funding, or a multinational fiat currency and world government based on my 50 year predictions either.

Mind you, the SOI was falling months ago, and it wasn’t too much of a wild guess to suggest that just maybe, possibly, a La Nina was on the way. Bryan Leyland did that here, and his global predictions are panning out reasonably well so far. (Brian 1, BOM -1.)

If government funding weren’t trying to pick the winners (which climate theory should they back? ans: none) then possibly Australia would have some weather forecasters with skills like Piers Corbyn or Joe Bastardi. Speaking of Piers, the UK media finally seems to be recognizing his talent.

The man who repeatedly beats the Met Office at its own game

Full Story Boris Johnson at The Telegraph

Piers Corbyn works in an undistinguished office in Borough High Street. He has no telescope or supercomputer. Armed only with a laptop, huge quantities of publicly available data and a first-class degree in astrophysics, he gets it right again and again.

Back in November, when the Met Office was still doing its “mild winter” schtick, Corbyn said it would be the coldest for 100 years. Indeed, it was back in May that he first predicted a snowy December, and he put his own money on a white Christmas about a month before the Met Office made any such forecast. He said that the Met Office would be wrong about last year’s mythical “barbecue summer”, and he was vindicated. He was closer to the truth about last winter, too.

He seems to get it right about 85 per cent of the time and serious business people – notably in farming – are starting to invest in his forecasts. In the eyes of many punters, he puts the taxpayer-funded Met Office to shame. How on earth does he do it? He studies the Sun.

He looks at the flow of particles from the Sun, and how they interact with the upper atmosphere, especially air currents such as the jet stream, and he looks at how the Moon and other factors influence those streaming particles.

How many billions have we lost thanks to farmers who might have been able to harvest early, or plant different crops, or avoid seeding in droughts, or any one of a thousand other choices that would help them to make the most of our highly variable climate.

There is a policy vacuum begging to be filled here. Will either side of politics in Australia spend a fraction of the carbon emissions reduction scheme to fly Piers Corbyn or Joe Bastardi out here and ask him to train up an Australian team to work on local conditions?

Hat tip to Val Majkus. Thanks!

Reference:

Vizard, AL, Anderson, GA and Buckley, DJ (2005) Verification and value of the Australian Bureau of Meteorology township seasonal rainfall forecasts in Australia, 1997-2005. Meteorological Applications 12: 343-355.

“Verification and value of the Australian Bureau of Meteorology township seasonal rainfall forecasts in Australia, 1997-2005

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