Storm forecasts to get aerial lift

An approaching typhoon usually means that aircraft are grounded, but this summer, the Japan Meteorological Agency will send up a typhoon-chasing observation plane to gather data that could help hone its prediction skills.

The experiment will start in July in cooperation with the United States, South Korea and other nations in an international effort to improve the accuracy of storm forecasts.

According to the plan released by the agency Friday, the experiment aims to minimize margins of error when predicting the path of a typhoon. The mobility of aircraft will allow the agency to gain more data to improve forecast accuracy.

So far, typhoon path forecasts have been based on atmospheric pressure, wind velocity and direction and other data gathered by observatories, observation vessels and balloons.

But the accuracy of predictions is often marred by "sensitive regions," where small changes in observation data can lead to forecast errors.

Agency officials hope the specially equipped aircraft, to be chartered from Germany, will collect observation data in sensitive regions located in wide swaths around an approaching typhoon.

The aircraft, with a team of five, will fly four hours per flight, encircling a typhoon and parachuting 10 to 15 weather reconnaissance devices, called dropsondes, into sensitive regions and other areas.

The agency is also planning to increase the number of typhoon observations made by the weather satellite Himawari 7 as well as balloons and ships.

In addition to the Japan Meteorological Agency, the Naval Research Laboratory and the National Oceanic and Atmospheric Administration of the United States and Yonsei University of South Korea will join the program.

Chinese and Canadian groups will also take part in the experiment slated to continue from late July to early October, the officials said.

Japan and South Korea will be in charge of observations above the seas around the Nansei island chain in the southernmost prefectures of Okinawa and Kagoshima.

Typhoons often change course abruptly in that area because of westerly winds. There are known sensitive regions in the area.

The United States will mainly cover observations in the Pacific Ocean area where typhoons spawn and another near the Aleutian islands, where typhoons weaken to become temperate low-pressure systems.(IHT/Asahi: May 12,2008)