Following Captain Cook
Recently, NOAA contracted a U.S. Tenix LADS (Laser Airborne Depth Sounder) subsidiary to survey vast swaths of Alaska coastline.
In Cold Bay, Alaska (population: approximately 60), a 15-member Tenix LADS crew set up shop in April 2003 to begin a three-month survey.
"We are dealing with very complex, rugged coastline here," project manager Darren Stephenson said from Cold Bay. "It would be very difficult for a ship to do this survey. We are looking mainly to spot the hazards, such as the rocks, in the shallow water," he said.
Hazard spotting has always been an important component of nautical charting. Prior to one Australian survey by Tenix LADS, pilot Neville Balding was surprised to find that the only usable charts dated back to the early 1800s, when British navigator Mathew Flinders famously charted much of the continent's coast.
"In one sense, the LADS pilots and the onboard surveyors are picking up where [legendary 18th-century British ocean explorer and cartographer James Cook] left off," said Philip Smart of the National Air Support company, which flies and maintains aircraft on behalf of Tenix LADS in Australia.
"They are the new pioneers, because they are charting unknown territory," Smart added.
Origins and Innovations
The origins of ALB date back to the late 1960s, when the U.S. Navy began to use airborne laser-based systems for submarine detection. Prototype ALB systems emerged in the late 1970s and early 1980s.
Today there are two leading ALB systems: SHOALS (Scanning Hydrographic Operational Airborne Lidar Survey), which is administered by the U.S. Army Corps of Engineers, and LADS Mk II, which is owned by Tenix LADS.
Over the past ten years SHOALS has conducted a wide range of surveys, from post-hurricane assessment in Florida to a survey of uncharted waters off Mexico's Yucatán Peninsula.
So far, ALB laser transmissions into water appear to have no ill effects on the environment. In fact, the laser beams are carefully calibrated to be "eye safe." That means that if you were standing on a boat and looking directly at the laser pulse coming from an ALB aircraft, you'd be safe.
Plus, NOAA's Longenecker argues, the environmental benefits of greater coastal mapping is immense. The data obtained can be used to better develop storm models as well as to evaluate the health of U.S. coastline. ALB data can also help prevent shipwrecks that can pollute pristine waters and cause human tragedies.
The work of ALB crews in Alaska, Australia, and around the world could mean the difference between a shipwreck and a safe journey.
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