11
Charles L Wrench RCRU Status of Observations at Chilbolton (CFARR) October 2004
Charles L Wrench
RCRU
Status of Observations at Chilbolton (CFARR)
October 2004
Presenter Name
Facility Name
Millimetre cloud radars at CFARR
94 GHz radar in cradle and 35 GHz radar on mount
Presenter Name
Facility Name
Status of millimetre wave cloud radars:• 94 GHz Galileo radar has been experiencing loss of transmitter power and apart from a few days of operation it has been switched-off since 9th April 2004. • Recent malfunction of the receiver is currently under investigation.
• 35 GHz Copernicus radar has been operating since early May 2004. The radar has two modes of operation: transmitting (1) coded and (2) uncoded pulses.
By adopting the pulse compression mode it is possibleto improve sensitivity by ~10dB.
The radar measures: Full Doppler spectrum, the spectral moments and the polarimetric parameters
Presenter Name
Facility Name
Specification of 35 GHz Copernicus radar:
• Transmitter is based on a programmable waveform generator driving a high-power pulsed amplifier tube (EIKA).
• The receiver is a dual channel, double-conversion superheterodyne with separate IF chains for simultaneous co-polar and cross-polar measurements.
• Dual-polarisation antenna (2.4 m) includes a fast transmit polarisation switch.
• Tx power 1.5 kW peak pulse• Range resolution 75 metres• Beamwidth 0.23 degrees• PRF 5000 Hz• Unambiguous velocity ~5.3 m/s• Minimum range in pulse compression mode ~500 metres
Presenter Name
Facility Name
Uncoded pulse
Coded pulse [Pulse CompressionGain ~10dB]
35 GHz Copernicus radar data
radar reflectivity velocity away from radar
Presenter Name
Facility Name
Uncoded pulse
Coded pulse [Pulse CompressionGain ~10dB]
35 GHz Copernicus radar data
radar reflectivity velocity away from radar
Presenter Name
Facility Name
UV Raman Lidar IR Lidar CT75K
Ceilometercollects backscatter
Lidars
Radiosonde comparisons with integrated water vapour profileperformed during July 2004
Presenter Name
Facility Name
Pyrgeometer & PyranometerBroadband Radiometers
Radiometers
Microwave radiometers
Retrieving LWP and IWVFrom 22.2 and 28.8 GHz
[37.5 GHz under investigation for instability]
Presenter Name
Facility Name
Additional measurements: One month of data.
Comparison of performance between pulsed radar and low powerFMCW unit (100mw Tx power)
Two examples:
FMCW - low power radar
Presenter Name
Facility Name
Non-Precipitating Cloud
Presenter Name
Facility Name
Precipitating Cloud
