As described in the July 1 issue of the journal Optics Letters, published by the Optical Society, the mobile lidar station can measure wind fields more accurately, which could help world-class athletes compete in international competitions, such as the Olympics. Ocean University is in Qingdao, which is hosting the sailing competitions of the XXIX Olympic Games and the Beijing 2008 Paralympic Games, and this technique is being tested in conjunction with the event.
"Wind is non-uniform even in a small sailing field," says 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. "Athletes could maximize their performances if they have the most accurate information to help them capture the wind."
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.
Because 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.
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.
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.
The research was funded by the National Natural Science Foundation of China, the Key Laboratory of Ocean Remote Sensing, the Ministry of Education of China and the China Meteorological Administration (CMA).
Paper: "A high spatial and temporal resolution mobile incoherent Doppler lidar for sea surface wind measurements" by Zhi-Shen Liu et al., Optics Letters, Vol. 33, No. 13, July 1, 2008 p. 1485-1487. For a copy of the paper, please contact Angela Stark, email@example.com or 202.416.1443.About OSA
Angela Stark | newswise
Scientists propose synestia, a new type of planetary object
23.05.2017 | University of California - Davis
Turmoil in sluggish electrons’ existence
23.05.2017 | Max-Planck-Institut für Quantenoptik
An international team of physicists has monitored the scattering behaviour of electrons in a non-conducting material in real-time. Their insights could be beneficial for radiotherapy.
We can refer to electrons in non-conducting materials as ‘sluggish’. Typically, they remain fixed in a location, deep inside an atomic composite. It is hence...
Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.
Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...
An Australian-Chinese research team has created the world's thinnest hologram, paving the way towards the integration of 3D holography into everyday...
In the race to produce a quantum computer, a number of projects are seeking a way to create quantum bits -- or qubits -- that are stable, meaning they are not much affected by changes in their environment. This normally needs highly nonlinear non-dissipative elements capable of functioning at very low temperatures.
In pursuit of this goal, researchers at EPFL's Laboratory of Photonics and Quantum Measurements LPQM (STI/SB), have investigated a nonlinear graphene-based...
Dental plaque and the viscous brown slime in drainpipes are two familiar examples of bacterial biofilms. Removing such bacterial depositions from surfaces is...
23.05.2017 | Event News
22.05.2017 | Event News
17.05.2017 | Event News
23.05.2017 | Physics and Astronomy
23.05.2017 | Life Sciences
23.05.2017 | Medical Engineering