For much of the past decade, RAP has been studying the characteristics,
physical causes and aviation impact of low-level turbulence induced
by air flow over terrain. In addition, RAP has played key roles in
designing, constructing and deploying real-time operational systems
to warn the aviation users about a presence of significant
terrain-induced hazards. RAP's heavy involvement in this field started
program in Hong Kong
where a new airport at Chep Lap Kok was
being built in close proximity to a major mountain barrier. After
extensive scientific studies that included nearly a year of field
observations and extensive high-resolution numerical modeling,
an operational system for detecting and forecasting the presence of
significant turbulence near the airport was built and deployed.
The system was integrated with the Terminal Doppler Weather
Radar (TDWR) system and continues to provide real-time hazard
information for Chep Lap Kok.
The knowledge and experience gained from the Hong Kong program were
further tested in a FAA-sponsored field program in Colorado Springs
in the wake of the unresolved crash of a United 737 there in 1991.
Although no specific clues to that crash were revealed, the Colorado
Springs study was able to show that the instruments and techniques
for detecting terrain-induced turbulence in Hong Kong were applicable
in the very different Colorado Springs environment.
More recently, RAP has been studying terrain-induced turbulence in the vicinity
of the Juneau International airport, Alaska. The
problem in Juneau is complicated by a complex terrain around
the airport, the need for very unique arrival and departure routes
to avoid the terrain, and frequent episodes of very low ceiling
and visibility. RAP has conducted two intensive field data collections
in the area and has generally confirmed that the conclusions of
the Hong Kong and Colorado Spring programs carry over into Juneau,
although the complexity of the Juneau situation and the harnesses
of the climate cloud those results somewhat. An operational system
for providing wind information of a crucial importance for aviators
has already been deployed there, and efforts are underway to upgrade
the system to provide specific terrain-induced hazard warnings.
Research Lead: Alex Praskovsky