Back in the late 1990s, researchers from the National Center for Atmospheric Research (NCAR) in Boulder, Colo., were investigating the potential for LIDAR-based runway windshear detection, and did a feasability study in Hong Kong for developing an "automated" system (one that generates automated alerts from taking continuous radar and sensor readings). But when NCAR first approached local officials about using LIDAR, they resisted, reports NCAR's Larry Cornman, who was deeply involved both with NCAR's LIDAR research and the initial Hong Kong study. At the time, that was a reasonable enough decision, Corman adds. That's because the technology was still very new and does not work as well as it does today.
NCAR's contract in Hong Kong ended before the new airport opened, and also before local officials changed their mind about LIDAR.
So the bottom line with TDWR is that it works very well when there's water droplets, and LIDAR shines when the sun does likewise and there's still plenty of dust. Because LIDAR works so well when the air is crowded with small particulates, the technology can be expected to work very well in a large city like Hong where there's a high level of pollution, Cornman tells Air Safety Week. By contast, in Juneau, Alaska, where NCAR conducted some of its LIDAR research, it was a very different situation. Like Hong Kong, the Alaskan capital presents some pretty tricky navigational problems because of its surrounding mountains. But the air is just too un-polluted (as of yet) to allow LIDAR to work very well.
Overall, rather than having one or the other type of technology, it's an ideal situation to have both TDWR and NCAR, as Hong Kong now has, Cornman adds.
Currently, the LIWAS hardware components deployed at Hong Kong Airport consist of the TDWR, the LIDAR, a number of anemometers and other sensors. There's also only one LIDAR device at the top of the air traffic control tower in between the two runways, which is not an ideal way to position the system, Greeves says. In a couple of years, a second LIDAR device will be installed at the north end of the airport.
>>Contact: Chi Ming Shun, Hong Kong Observatory, 852 2926 8435, firstname.lastname@example.org; Brian Greeves, IFALPA, 852 9456 9650, email@example.com; Larry Cornman, NCAR, (303) 497-8439, firstname.lastname@example.org
Defense against this force of nature has several routes, most notably predictive and reactive