Radar Wind Profiler
The Facility for Ground-based Atmospheric Measurement (FGAM) mobile wind profiler is a 'clear-air' UHF Doppler radar system designed by Degreane Horizon to measure both wind speed and direction 24 hours a day under all weather conditions. 'Clear air' radars detect small irregularities in backscattered signals due to refractive index inhomogenieties caused by turbulence. In the lower troposphere the refractive index inhomogeneities are mainly produced by humidity fluctuations. The 'clear-air' Doppler shift provides a direct measurement of the mean radial velocity along the radar beam.UHF radars also observed strong echoes from precipitation. The wind profiler operatres at 1290 MHz with a peak power of 3.5 kW and beam width of 8.5°. The radar consists of three panels to emit and receive three separate beams, each panel being an array of 64 dipole antennas. The vertical beam measures the vertical component of the wind and the two at elevation of 73° and orthogonal azimuths sample radial velocities that have contributions from both vertical and horizontal wind components to enable full wind vectors to be calculated.
Deployment history
Summer 2002, NAMBLEX , Mace Head, Ireland.
Autumn 2002 Intercomparison project, Met office, Cardington, Bedford.
Summer 2003 TORCH, Writtle, Chelmsford, .
Spring 2004 TORCH, Weybourne, Norfolk.
Summer 2004 CSIP, Ashmansworth.
Operation requirements
Wind profiler folds up onto a compact trailer.
weighing ~ 1 tonne that can be towed behind a vehicle such as a Land Rover.
Operational dimension - L x W = 7.65 x 4.2 m.
Packing up ~ 4 hours, Set-up time ~ 1 day.
Power requirements two 13 A plug sockets.
Specifications of the UFAM wind profiler | |
Transmitter Frequency | 1290 MHz |
Transmitter Bandwidth | 10 MHz |
Beam Width | 8.5° |
Peak Power | 3500 W |
Aperture | 4 m2 |
Antenna gain | 25 dBi |
Average power 'low mode' | 40 W |
Average power 'high mode' | 100 W |
Minimum height | 75 m |
Maximum height | 4.5 km |
Resolution dependent on pulse width | 50 m to 375 m |
Instrinsic wind speed accuracy | < 1m/s |
Instrinsic wind direction accuracy | < 10° |
Periodicity of profile computation | Adjustable from 2 minutes |
Operational temperature | -20 °C to 30 °C |
Operational relative humidity | 5% to 95 % without condensation |
Resistance to wind | 20 m/s (average) 40 m/s (gusts) |
Power supply | 230 V +10% -15 %, single phase |
Sample measurements from CSIP 2004.
Sample measurements from CSIP 2004.
The Radar Wind Profiler is supported by the NCAS Facility for Ground-based Atmospheric Measurement (FGAM).