Picture courtesy of NOAA
The USA and Caribbean are due for another battering during the 2002 Atlantic hurricane season according to weather experts. But how can they predict them so far in advance?
Scientists from the Tropical Storm Risk consortium are forecasting eight hurricanes in the Atlantic basin as a whole. Two are expected to strike USA shores, and one to cross the Caribbean Lesser Antilles any time from 1st June to 30th November 2002.
The reason for their confidence is partly due to the nature of tropical weather. The TSR lead scientist, Dr Mark Saunders from University College London explains: "In the tropics, seasonal weather (i.e. the weather over a period of months) is forced by sea temperatures which change slowly and can be predicted months in advance."
He adds that: "In contrast, seasonal weather at northern European mid-latitudes, is affected largely by random motions in the atmosphere which are not predictable beyond about a week."
TSR's scientific team, who include climate physicists, meteorologists and statisticians from University College London and the Met Office, base their projections on 'hindcasting'.
They build a model using data from 1950 to 1985 and test it on 1986-2000 data. This enables them to see what would have been predicted had the model been available in those years. And so far TSR have found it to be an accurate method. They predicted the 2001 Atlantic hurricane season, the 2001 NW Pacific typhoon season and the tropical storms experienced in the Australian region 2000/2001.
The two main factors they look for in predicting overall Atlantic hurricane activity are; the speed of the trade winds plying between west Africa and the Caribbean, and how warm the sea waters are in this same region during August and September. "Hurricanes are linked to weaker than normal trade winds and warmer than normal sea temperatures in the tropical north Atlantic," says Dr Mark Saunders. Both these conditions are anticipated for 2002 according to TSR.
Hurricanes can cause devastation, not just to the natural environment, but also to business. The average annual damage bill in the USA alone is estimated to be £3.5 billion (US $5.1 billion) from 1926-2000. TSR developed out of TSUNAMI, a UK government initiative that brought together experts from the insurance and science world to improve risk assessment. As a result, TSR's work is directed primarily at insurers. However, it is also useful to power and energy, tourism and shipping, who can prepare and hopefully minimise their losses.
Related Links:
- Lifecycle of a Hurricane
- Naming Hurricanes
- Hurricane Season
- Tropical Storm Risk's website
- TSUNAMI
