World-first application of AMDAR observations for windshear reporting

The Observatory makes a first step in the world in applying AMDAR (Aircraft Meteorological DAta Relay) weather observations measured onboard in windshear reporting. AMDAR weather reports contain wind and temperature information measured along the aircraft flight path. The high data resolution of AMDAR reports as well as the availability of such weather reports in near real-time facilitates monitoring of windshear in and around the airport.

Since 2004, the Hong Kong Observatory started operational reception and dissemination of automatic AMDAR weather reports made by computers onboard of a commercial aircraft. Through the collaboration among the Observatory, Cathay Pacific Airways and the Civil Aviation Department, additional AMDAR reports have been received from five more Cathay Pacific Boeing-747 aircraft since September 2005. At present the Observatory receives about 1000 AMDAR weather reports daily directly from these aircraft.

Earlier this year, experiments were conducted in applying AMDAR observations for low-level windshear reporting. Headwind changes experienced by aircraft during arrival and take-off were computed from AMDAR reports received and compared with the high density raw data recorded on the aircraft. Result indicates that the AMDAR reports are useful in monitoring low-level windshear.

Starting from early 2006, these AMDAR observations will be used in operational windshear reporting to alert pilots of the arriving aircraft at the Hong Kong International Airport (HKIA).

Schematic illustrating how the AMDAR observations received from aircraft are used to automatically generate a windshear warning message for reporting the presence of windshear to pilots through the Automatic Terminal Information Service (ATIS)