Clouds have a great impact on the Earth energy balance and monitoring clouds has great importance on weather forecasting and on understanding climate change. The main purpose of cloud radars is to investigate clouds properties. Millimetre wave cloud radars typically operate at frequency range between 35GHz and 94GHz. They introduce an enhanced sensitivity that enables detections of cloud micro properties such as cloud droplets and ice crystals.
RAL Space's Millimetre Wave Technology (MMT) cloud radar has a 94GHz Frequency Modulated Continuous-Wave (FMCW) cloud radar. It is a compact and lightweight instrument that provides unique information about the vertical distribution of water droplets and ice crystals in mist, fog and clouds. The MMT cloud radar is a solid state radar, emitting a relatively low power and long, linearly chirped, pulse at a frequency of 94 GHz. During a pulse, about 200 mW of millimetre wave radiation is collimated into a beam by a parabolic mirror and is then transmitted towards the zenith. A fraction of the radiation that is backscattered by hydrometeors is collected by a second parabolic mirror and focussed into the receiver. Distance to target information is obtained by measuring the instantaneous difference frequency between transmitted and received signals using a Fast Fourier Transform data processing routine.
The radar was built for and in collaboration with the UK Met office and it went through a series of UK trials in Camborne, Aberystwyth, Cardington, and Chilbolton. International deployment in Payerne, Switzerland, and Mauritius were also accomplished. Measurements campaigns have revealed the potential of the instrument for meteorology, forecasting, cloud physics and aviation.
Technical Details
- Radar type: Bistatic, zenith sounding, frequency modulated continuous wave radar
- Frequency: 94 GHz
- Radiated power: 200 mW
- Maximum range: Selectable, from 2 km to 32 km
- Resolution (proportional to maximum range): 15 m on 8 km range setting
- Dynamic range: > 40 dB
- Optionally incorporates an unstablised 94 GHz radiometer to measure sky temperature
- Front-end dimensions and mass: 1.5 m x 0.8 m x 0.8 m, 70 kg
MMT Cloud Radar Measurements
Credit: STFC RAL Space
For more information please contact: RAL Space Enquiries
