From The Japan Times:
The number of typhoons this year could turn out to be the lowest on record, which experts theorize could be a result of the El Nino phenomenon lasting until this spring and the summer’s powerful high-pressure system in the Pacific.
As of Saturday, 14 typhoons — tropical cyclones generated in the Northwest Pacific or the South China Sea north of the equator with a minimum wind velocity of 61.9 kph — have been spawned this year.
The Meteorological Agency, which has been keeping statistics on typhoons since 1951, said the lowest number — 16 — was in 1998. The average per year between 1971 and 2000 was 26.7, while the most on record is 39 in 1967.
The agency believes the well-developed Pacific high that brought this summer’s heat wave has weakened the atmosphere’s convective activity in the sea, nipping the development of rain clouds, which help produce typhoons.
El Nino can similarly work to dampen the air’s convective activity in the sea near the Philippines, and the latest phenomenon is believed to have contributed to decreasing the number of typhoons this year, agency officials said.
Simulations run by the agency show that progress in global warming will reduce the number of typhoons but make each one more intense.
Dr. Ryan Maue’s ACE plot also shows a low year. He adds: “The agency should have stopped when they were ahead and not mentioned global warming during a historically quiet Typhoon season. Their explanation must have been lost in the translation because almost everyone has noticed that there has been a rapidly developing and intense La Nina during the summer and fall of 2010. Put very simply, the previous historically quiet Typhoon seasons in the Western Pacific basin are usually associated with La Nina. Global ACE is still near 33-year lows, and shows no signs of picking up anytime soon.”
Figure: Year-to-Date (November 21) Accumulated Cyclone Energy (ACE; units: 104 knots2) for the Northern Hemisphere as a whole (top blue time series) and for the combination of the Western North Pacific (WPAC), Eastern North Pacific (EPAC), and Northern Indian (NIO) basins (bottom red time series). The difference between the two lines is therefore the contribution of the North Atlantic hurricane basin.