Laser-based system can sample large areas

A team of researchers at the Ocean University in Qingdao, China has developed and tested a mobile lidar (light detection and ranging) station that can accurately measure wind speed and direction over large areas in real time – an application useful for aviation safety, weather forecasting and sports. The mobile lidar station can measure wind fields more accurately, and this technique is being tested in conjunction with the sailing competitions of the XXIX Olympic Games and the Beijing 2008
Paralympic Games,

In the Qingdao sailing area, where this summer’s competitions will take place, only four buoys, one boat and one tower are available to measure sea surface winds within a competition area of approximately 10 square kilometers. Professor Zhi-Shen Liu and his lidar group, composed of research scientists and graduate students, 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.

The advantage of Doppler lidar, says Liu, is that it can quickly sample a large area, providing a much finer map of winds than buoys alone. He and his group have developed a lidar bus, which can move equipment to the experiment field conveniently. Last year, they successfully tested their new bus at the 2007 Qingdao International Regatta sailing event. They moved the bus to the
seashore near the sailing field, and made a horizontal scan over the sea surface, making the measurement in real time and then uploading the data to the local meteorological station every 10 minutes. They envision a similar effort in the upcoming Olympic and Paralympic games.

Complete story: Science Daily