Technical Aspects and Scientific Applications of New VHF Wind Profiler Radar at 205 MHz

A state-of-the-art VHF wind profiler radar operating at 205 MHz frequency is installed at Cochin University of Science and Technology, Cochin (10.04^oN; 76.33^oE), a tropical coastal station, located in the southwest peninsular region of Indian Subcontinent. This unique Stratosphere Troposphere (ST) wind profiler radar is first of its kind in the World, designed and developed at the 200 MHz frequency range. Compared to the conventional 50 MHz radars, the 205 MHz radar is less affected by cosmic noise, therefore the accuracy of measurement is much better. Moreover, the radars operating in UHF ranges are known to get saturated under rainy conditions, while such issues do not affect the 205 MHz radar. It is highly cost-effective comapred to 50 MHz radars, and require only lesser real estate for installation. The 205 MHz radar comprises of 619, three element Yagi-Uda antennae with a power aperture product of 1.6x10⁸ Wm² and is capable of providing accurate three-dimensional wind profiles for an altitude range from 315 m to 20 km and above. This radar has been setup mainly for the study of the dynamics of the Asian summer monsoon. The technical details and some of the scientific applications of the 205 MHz are being presented. The radar wind profiles have been validated against collocated GPS-radiosonde measurements. The radar and radiosonde profiles show very good similarity; the correlation coefficients between 205 MHz wind profiler radar and GPS radiosonde show 0.99 and 0.93 for zonal and meridional winds, respectively. The standard deviation of the radar measurements with respect to radiosonde measurements is found to be 1.85 ms^-1 for zonal wind and 1.66 ms^-1 for meridional wind. Some interesting scientific applications resulting from this radar, like the derivation of turbulent eddy dissipation rate, determination of tropical tropopause, detection of interia-gravity waves etc, will be presented. Furthermore, the radar is also capable of detecting echoes from the ionosphere. The 205 MHz radar at Cochin India, is an excellent observational facility for understanding the process in the troposphere, lower stratosphere as well as in the ionosphere.