RSS Feed

The Fujiwara Effect

Posted on

                                                          (also known as the Fujiwhara effect.)

In January 2010 there were two tropical cyclones in the Coral Sea at the same time.
Neville, close to our coast, and Olga rapidly approaching Neville from the East.   Two systems perfectly suited to begin the phenomenon known as the Fujiwara effect.

Dr Sakuhei Fujiwhara was a Japanese meteorologist in 1921 who, for reasons known only to himself, was farnarkling  around with laboratory experiments on vortexes and whirlpools in water. 
Maybe a childhood fascination with water disappearing down plug holes had opened his door to this scientific pathway.
Be that as it may or may not, he discovered unexpected interactions occurring when one vortex came under the influence of another, and it led him to postulate that similar effects would occur in the Earth's atmosphere, which behaves in a similar manner to the liquids he was experimenting with.

Only after weather satellites were launched in the 1960's could scientific proof be obtained, and observations made, to confirm his theories.

When two similar strength cyclones approach each other they will tend to cylindrically rotate around each other about a central pivot point determined by the relative strength of each system.

It is a relatively uncommon occurrence.  Perhaps twice a year in the Pacific ocean, and once every three years in the Atlantic.
(The difference explained simply because there are more cyclones each year in the Pacific.)

The two cyclones will rotate like a slowly turning horizontal dumbbell in a movement known as a Fujiwara dance or waltz.

The Fujiwara effect typically involves four stages.

1. Approach and capture; the orbits of the 2 storms begin to interact.
2. Mutual orbit;  begin Fujiwara dance.
3. Merger;  one storm if more intense will trap the smaller storm.
4. Escape; one storm may depart from the Fujiwara effect, or
    upper level atmospheric influences may cause the storms to
    split and resume independent courses.

Neville and Olga demonstrated this final scenario, making monkeys out of the forecasters attempting to predict tracks for the two systems.  Neville was fractured and flung more than 100km South, while Olga weakened into a rain depression on a westward track bringing drenching rain to us as well as a huge area of arid Northern and Central Australia.
Our rain gauge measured 548mm (22") in 4 days.

Isn't weather, nature and science absolutely fascinating and full of wonder?

Please forgive this burst of unrestrained meteorological enthusiasm.

P.S  "Farnarkle" is a little known Australian word meaning to "mess around with",
or more accurately "fart around with" something.

Read and post comments


Send to a friend

About GOF

"Life is like a sewer. What you get out of it, depends upon what you put into it." (Tom Lehrer)

11 responses »

  1. Your burst of meterological insight is highly welcomed from where I stand. This was riveting. I'm reminded of fractals – the way nature behaves and appears the same in patterns on both small and large scales – like radial symmetry.
    Cyclones are neat. I could totally see how a kid would be obsessed with that. I wonder if the video game "revolution" has denied the next great scientist from being bored enough to ponder those things.

  2. Thanks Emmi.Cyclones are neat.Well, in theory. Not so much so when you are in the middle of a category 4 or 5 one however. The science and physics of the atmosphere provides an endless source of interest for me. While weather forecasters have very little success in predicting weather, there is always great scientific explanations available after the event for why they stuffed up. :-)Maybe there is something in some video games to stimulate imagination? Interesting subject. I think we will always have enough inquisitive young intellectuals to drive new scientific discovery.

  3. They are neat the way black holes are neat. Of course thanks to global warming and coral reef / mangrove destruction, those cyclones are taking more lives and economies.
    Some people say video games have their upsides and of course computers were a huge boon to us, so who knows…..I do think boredom advances scientific discovery. 🙂

  4. .I do think boredom advances scientific discovery. :)Then I reckon I'm on the verge of a humungous scientific breakthrough:-)They are neat the way black holes are neat.Interested to read the other day about the stream of "stuff" that comes out of black holes as well as what goes in. I love science:-)

  5. Thanks for that, GOF. I'd never heard of the Fujiwara effect. But then I'd never heard of "farnarkle" either. I can see I've lived a sheltered life.

  6. How very interesting. I do think they are developing better models all the time to help with predicting the weather – not so much predicting the actual weather but what will happen IF this occurs or that occurs. They were pretty spot on with the snow storm we just had – they kept throwing computer simulation models on the screen. They are getting better at tracking storms. The poor manservant was on an 8 day observing rain and didn't get any observations because of the cyclone's effect on NSW skies.

  7. But then I'd never heard of "farnarkle" either. I can see I've lived a sheltered life. I'll keep up the supply of useless information Snowy while you deal with matters of greater importance 😉

  8. They are getting better at tracking storms. Certainly a lot better Emjay. With cyclone Larry they predicted an exact track 2 days in advance, but this system had meteorologists totally bewildered until it settled down, then they predicted Olga's subsequent loop around the Gulf of Carpentaria and eventual southward track into NSW where it messed around with the manservants "observings".

  9. Still trying to work "cactused" into the American lexicon, btw. I keep forgetting farnarkle!

  10. Still trying to work "cactused" into the American lexicon, btw. I keep forgetting farnarkle! Somehow I think "cactussed" is just more appropriate, geographically and botanically to your continent. Keep up the good work m-t 🙂

  11. You can thank John Clark for it Snowy.I think he was having "a go" at cricket.


Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

%d bloggers like this: