W-Band Cloud radar (JOYRAD-94)

W-Band Cloud radar (JOYRAD-94)

Cloud radar JOYRAD-94 installed at Jülich

Principle

The W-Band cloud radar is a Frequency Modulated Continuous Wave (FMCW) Radar that transmits saw tooth frequency chirps at 94 GHz. In this way, vertical profiles of reflectivity, Doppler velocity, Doppler spectral width are detected from 150 m to 10 km above ground. Given these measurements, information on the macrophysical (cloud boundaries, type of cloud particles) and microphysical (e.g., liquid and ice water content) properties of the detected cloud can be derived. The radar is operated in a vertically pointing mode. Additionally, the system is equipped with a passive radiometric channel at 89 GHz that is sensible to cloud liquid water. Passive and active receivers are fed by the same antenna, i.e. a perfect beam overlap is accomplished.

Measurement modes

Vertically pointing observations with integration times up to 1 seconds, variable chirp-tables possible (Doppler resolution, range resolution)

JOYCE-CF Standard Operation Procedures

Standard measurement mode is vertically pointing, 5 seconds integration time

Calibrations and data quality assurance procedures

Check with co-located disdrometer to find out reflectivity offsets
Consistency check with other cloud radars

Data availability

Data are available via request please fill the data request sheet and send it to info@joyce.cloud

Dataset	Temporal resolution	File size	Filename	Remarks
Radar moments, Liquid water path	5 seconds	1 file per hour (8-12 MB)	mirac_jue_-a_YYYYMMDDHHMMSS_P01_ZEN_compact.nc

Composite products using W-Band radar data

Dual-wavelength ratio Ka/W-Band Link to Quicklooks

Link to current observations

Data quicklooks can be found in the JOYCE quicklook archive

Measurement examples

Example time series of MiRAC-A observations at JOYCE (radar moments / LWP)

JOYRAD-94 History

Period	Place	Project
14/06/2019 - today	AWIPEV at Ny-Ålesund, Norway	(AC)3
23/03/2018 - 06/03/2019	Iquique, Chile	CRC1211
10/06/2016 - 26/07/2017	AWIPEV at Ny-Ålesund, Norway	(AC)3
16/10/2015 - 23/03/2016	Research Center Jülich, Germany	JOYCE

MiRAC-A History

Period	Device	Place	Project
11/12/2020 - today	MiRAC-A	Research Center Jülich, Germany	JOYCE
08/2020 - 09/2020	MiRAC-A	Polar 5, Svalbard
31/05/2019 - 08/01/2020	MiRAC-A	Research Center Jülich, Germany	JOYCE
03/2019 - 04/2019	MiRAC-A & -P	Polar 5, AFLUX campaign, Svalbard	(AC)3
28/07/2017 - 08/10/2018	MiRAC-A & -P	AWIPEV Ny-Ålesund, Svalbard	(AC)3
05/2017 - 07/2017	MiRAC-A & -P	Polar 5, ACLOUD campaign, Svalbard	(AC)3

MiRAC-A installed at Ny-Ålesund

Technical Specifications

Parameter	Specification	Remark
Frequency	94 GHz ± 100 MHz	corresponds to wavelength of 3.19 mm; adjustable by software between 92.3 and 95.7 GHz
IF Range	350 kHz to 3 MHz
Transmitter Power	~ 2 W	solid state amplifier
Antenna gain	51.6 dB
Beam Width	0.48° FWHM
Polarisation	V
System Noise Figure	3 dB
Dynamic Range	-54 dBZe to +20 DBZe at 1km height, -45 dBZe to +20 dBZe at 3 km height, -36 dBZe to +20 dBZe at 10 km height
Ranging	50 m to 18 km
Calibration	Transmitter power monitoring, Receiver Dicke switch (for radar and DD channels), Hot/Cold absolute receiver calibration	Accuracy 0.4 dB
A/D Sampling Rate	8.2 MHz
Profile Sampling Rate	0.2 s to 30 s
Vertical Resolution	1 m to 100 m	(user selectable)
Doppler Resolution	± 1.5 cm/s
Doppler Range	± 18 m/s max.
Chirp Variations	4 typical	10 possible, re-programmable
Passive Channels	89 GHz
Data Products	Reflectivity, Doppler-velocity, Spectral Width, Higher Moments, Doppler Spectra, LWC profiles
Data Formats	proprietary binary, netCDF (conformity with CF convention), ASCII (only moment profiles)
Rain / Snow Mitigation System	Super blower for rec. / transm. radome (2000 m³/h each)	Optional heater modules (2 kW to 4 kW)
Weight	Radar main body: 100 kg, Table: 130 kg, Air conductors: 25 kg
Power Consumption	220 V AC, 50-60 Hz, Radar: 400 W, Blowers: 1000 W
Manufacturer	RPG

Table of Contents