Wednesday, January 24, 2007

This Is The Last Of It...I Swear

OK, just one more. It has been claimed that hurricanes are lasting longer now because of global warming, so I had a look.

The average tropical storm duration in the Atlantic for the last 40 years has been 8.28 days. (Again I'm using data from Unisys.)

Breaking them up we find:

1967-1986: 7.83
1987-2006: 8.74

Aha! It looks like the average length of storms has increased almost a full day (around 11.6%.) However, if we break it down by decade we can see something a little bit different:

1967-1976: 8.37 (1% above 40 year mean)
1977-1986: 7.28 (12% below 40 year mean)
1987-1996: 8.79 (6% above 40 year mean)
1997-2006: 8.68 (4% above 40 year mean)

It would seem to make more sense saying that the decade from 1977-86 had abnormally short storms than to say we are having abnormally long storms now.

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