The Advanced Operational Aviation Weather System (AOAWS) in Taiwan

This paper describes the development and implementation of an Advanced Operational Aviation Weather System (AOAWS) in Taiwan. The AOAWS project is a cooperative effort that includes scientific, technical, engineering and administrative activities between the Civil Aeronautics Administration (CAA) of Taiwan and the University Corporation for Atmospheric Research (UCAR) in the USA. The AOAWS is an aviation weather system modernization project, which began on 1 July 1998 and runs through 30 June 2003.

The AOAWS system capabilities cover the terminal aerodrome and Taipei Flight Information Region (FIR) domains. The project includes the procurement and implementation of Low-Level Windshear Alert Systems (LLWAS) for Sungshan and Chiang Kai Shek (CKS) airports, an ASR-9 Wind Shear Processor (WSP) system for Kaohsiung airport, implementation and operation of the MM5 numerical weather forecast model, and the development of an advanced display technology for a variety of end users (e.g., aviation forecasters, air traffic controllers, pilots, and airlines).

The CAA°¦s LLWAS will be functionally equivalent to the FAA LLWAS system known as Phase III LLWAS. The two CAA LLWAS systems will provide windshear, microburst, and runway wind information to the Air Traffic Control Towers and Airport Weather Stations at Sungshan and CKS airports. The LLWAS contract has been awarded and the systems are expected to be in full operation at both airports by March 2001. The ASR-9 WSP system will be completed and operational by 2002.

The MM5 system is currently running on a 6-hour update cycle in a nested configuration using a 3-domain grid with a spacing of 135/45/15-km. The MM5 model will be run on a 3-hour update cycle with a 4-domain, 135/45/15/5-km configuration in 2002. The high-resolution domain (5-km grid) will cover the Taipei FIR. A 3-Dimensional Variational Analysis (3DVAR) data assimilation system is currently under development for the CAA°¦s MM5 model. The 3DVAR capability will be implemented in 2001.

The MM5 model output will be combined with observational data and aviation weather products will be generated. The primary display capability includes a graphical Multi-dimensional Display System that provides both 2- and 3-dimensional analyses and forecast products (plan view and route specific), designed for non-meteorological users, and a Model Display for displaying the numerical weather prediction guidance products for forecasters. A web system will also be implemented which will provide access points to the advanced aviation weather products for remote users, including pilots and airlines.