Washington, July 1 : Participants vying for the gold during the sailing events at the Olympics have a new tool to lend them a helping hand - a mobile lidar (light detection and ranging) station.
The station, developed and tested by scientists at the Ocean University of China, can accurately measure wind speed and direction over large areas in real time.
It can measure wind fields more accurately, which could help world-class athletes compete in international competitions, such as the Olympics.
"Wind is non-uniform even in a small sailing field. Athletes could maximize their performances if they have the most accurate information to help them capture the wind," said Professor Zhi-Shen Liu of the Key Laboratory of Ocean Remote Sensing, Ministry of Education of China, Ocean University of China, who led the research.
In Olympic sailing, individual competitors or teams of athletes sail various classes of sailboats in timed trials over a single course. The contest requires them to navigate upwind, downwind and everything in between. Their final time depends on numerous factors, including the boat design, the skill of the sailors, course difficulty and ocean currents. Perhaps the most important factor, though, is how well the athletes can harness the wind that fills their sails.
As the wind constantly changes speed and direction, athletes and coaches hope to have the best information at the start of a run. On cloudy, rainy days, the standard meteorological tool of Doppler radar can accurately provide wind field information. When no clouds are present, however, Doppler radar is ineffective. The best wind data on clear days comes from ocean buoys and land stations that use wind cups and ultrasonic anemometers to measure wind speed.
The researchers have been working with an optical remote sensing technology called Doppler lidar, which they are applying for weather and environmental research.
Lidar works by scattering laser beams off atmospheric aerosols or molecules. Doppler lidar takes advantage of the fact that when these aerosols or molecules are moving in the wind, the scattered laser light changes frequency -- the same way an approaching car has a higher pitched sound than a car driving away.
Liu said that the advantage of Doppler lidar is that it can quickly sample a large area, providing a much finer map of winds than buoys alone.
The study is published in the latest issue of the journal Optics Letters, published by the Optical Society.