Table of Contents
Dual-frequency cloud radar (JOYDURADO)
Cloud radar JOYDURADO installed at Jülich
Principle
JOYDURADO consists of two Frequency Modulated Continuous Wave (FMCW) radars that transmits saw tooth frequency chirps at 35 and 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. From the dual-wavelength ratio and the polarimetric capabilites, additional information on particle shape and size can be derived. The two radars are mounted on a common frame so that both instruments can scan both in azimuth and elevation.
Additionally, the system is equipped with two passive radiometric channels at 31.4 and 89 GHz that are sensible to cloud liquid water. Passive and active receivers are fed by the same antennas, 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
- Calibration of passive channels using HATPRO microwave radiometer spectra
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 |
Link to current observations
Data quicklooks can be found in the JOYCE quicklook archive
JOYDURADO History
| Period | Place | Project |
|---|---|---|
| 20/06/2024 - today | Research Center Jülich, Germany | JOYCE |
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 |