METEOROLOGISTS USE NOAA TRAINING DURING FLIGHTS INTO TYPHOON DUJUAN

Meteorologists in Chinese Taipei, in collaboration with the Commerce Department’s National Oceanic and Atmospheric Administration (NOAA), conducted the first of a series of aircraft surveillance missions around typhoon Dujuan Aug. 31 in the Western Pacific Ocean.

The project, named DOTSTAR, Dropsonde Observations for Typhoon Surveillance near the Taiwan Region, builds upon work pioneered at NOAA’s Hurricane Research Division (HRD) in Miami, Fla., to improve track forecasts for tropical cyclones. The key to the project is the use of airborne sensors, called dropwindsondes, released from jet aircraft flying above 42,000 feet in the environment of a tropical cyclone. These sensors gather temperature, humidity, pressure, and wind velocity information as they fall to the surface.

“Information from the surveillance flights is transmitted by a satellite phone aboard the aircraft in near real-time to the Chinese Taipei Central Weather Bureau (CWB),” said project lead Dr. Chun-Chieh Wu from the National Taiwan University (NTU). “The data are used immediately in the CWB's 72-hour typhoon forecast report. The data will give us a much better handle on storm development and conditions and help us to improve the accuracy of forecasts of typhoon tracks by up to 30 percent.”

The initiative is a collaborative effort between researchers from the NTU, CWB, and the National Science Council of Chinese Taipei, partnered with scientists at HRD and the NOAA National Centers for Environmental Prediction (NCEP). During the 2002 hurricane season, four researchers from the National Taiwan University, the Chinese Culture University, National Central University, and CWB in Chinese Taipei worked with HRD scientists, learning the operational and scientific aspects of using aircraft to sample the hurricane environment.

Since 1997, the NOAA National Hurricane Center (NHC), NOAA Aircraft Operations Center and NOAA HRD have gathered data with the Gulfstream-IV-SP jet aircraft in the environment of hurricanes threatening the United States. The data are processed aboard the aircraft and sent to forecasters at NHC and to NCEP for assimilation into numerical forecast models.

The goal is to improve the data that go into the models that predict hurricane track and intensity to improve NHC forecasts during the time that hurricane watches and warnings are posted. “Similar missions are routinely conducted in the Atlantic with NOAA's Gulfstream-IV jet aircraft, and these have improved track forecasts by about 20 percent on average,” said Dr. Sim Aberson, a meteorologist with HRD. “Five missions have already taken place this year in Hurricane Claudette and Tropical Storm Erika before each made landfall on or near the coast of Texas.”

The typhoon surveillance missions this year will be carried out on board an Astra SPX jet from Chinese Taipei’s Aerospace Industrial Development Corporation. With TND $24 million in annual funding, the DOTSTAR project, now in the second year of a three-year schedule, will conduct seven to eight flight missions both this year and next year. Results from this study could provide very useful information to typhoon researchers and forecasters in the Western Pacific Ocean.

The Chinese Taipei group maintains close communication with HRD and learning helpful scientific ideas and technical experience. “With good collaboration with our HRD friends, we believe that our project can be very successful,” said Wu.

The Commerce Department's National Oceanic and Atmospheric Administration (NOAA) Office of Oceanic and Atmospheric Research is dedicated to enhancing economic security and national safety through research to better understand weather and climate-related events and to manage wisely our nation's coastal and marine resources.

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