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Table of Contents
Cloud radar JOYRAD-35
Cloud radar JOYRAD-35 installed at Jülich
Principle
JOYRAD-35 is a scanning Doppler cloud radar MIRA-35 manufactured by METEK GmbH. It is installed at the Forschungszentrum Jülich as part of JOYCE. The radar transmits a linearly polarized signal at 35.5 GHz (Ka-Band) and receives co- and cross-polarized signals simultaneously. In this way, vertical profiles of reflectivity, Doppler velocity, Doppler spectral width and of linear depolarization ratio are detected from 150 m to 15 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 has full 3D-scanning possibilities for the entire upper hemisphere.
Measurement modes
- Vertically pointing observations with integration times up to 1 seconds.
- Full azimuth/elevation scanning capability for horizontal variability of clouds as well as 3D wind vectors in clouds
JOYCE-CF Standard Operation Procedures
- Standard measurement mode is vertically pointing, 2 second integration time
- Every 30 minutes one azimuth scan at 83° elevation angle with 6° azimuth resolution (duration ~2 minutes) for horizontal wind within clouds and the boundary layer (if sufficient insects are present)
Calibrations and data quality assurance procedures
- Check with co-located disdrometer to find out reflectivity offsets
- Consistency check with other cloud radars
Data availability
The following data products are provided via Cloudnet with a temporal resolution of 30 seconds. If you would like to have additional data with better resolution or raw Doppler spectra data request sheet and send it to info@joyce.cloud
| Dataset | Temporal resolution | File size | Filename | Retrieval |
|---|---|---|---|---|
| Radar reflectivity factor | 30 seconds | 1 file per day (30-50 MB) | YYYYMMDD_juelich_categorize.nc | |
| Doppler velocity | 30 seconds | 1 file per day (30-50 MB) | YYYYMMDD_juelich_categorize.nc | |
| Spectral width | 30 seconds | 1 file per day (30-50 MB) | YYYYMMDD_juelich_categorize.nc | |
| Linear depolarization ratio | 30 seconds | 1 file per day (30-50 MB) | YYYYMMDD_juelich_categorize.nc | |
| Profiles of horizontal wind | 30 minutes | 1 file per day (30-50 MB) | YYYYMMDD_joyrad35_wind_profile.nc | |
| Doppler spectra |
- Dual-wavelength ratio Ka/X-Band and Ka/W-Band Link to Quicklooks
- Cloudnet target classification uses Radar moments data from JOYRAD-35. Combined with microwave radiometer and ceilometer observation, clouds are characterized by their geometrical extent as well as their microphysical properties. Data are available via ACTRIS cloudnet website
Link to current observations
Data quicklooks can be found in the JOYCE quicklook archive
Measurement examples
Example time series of JOYRAD-35 observations (radar moments / horizontal wind)
Example time series of Cloudnet target classification
JOYRAD-35 History
| Period | Place | Project |
|---|---|---|
| 2017 | Instrument upgrade | |
| 09/03/2012 - today | Research Center Jülich, Germany | JOYCE |
| 08/11/2011 - 08/03/2012 | Munich Airport, Germany | iPort campaign |
| 03/2011 - 07/11/2011 | Research Center Jülich, Germany | JOYCE |
Cloud radar JOYRAD-35 installed at Jülich
Technical Specifications
| Parameter | Specification | Remark |
|---|---|---|
| Frequency | 35.5 ± 0.15 GHz | corresponds to wavelength of 8.5 mm |
| Peak power (max) | 25 kW | |
| Average power | ~ 24 W | |
| Pulse width | 200 ns | adjustable (100, 200, or 400 ns) |
| Pulse repetition frequency | 5 kHz | adjustable (5-10 kHz) |
| Minimum height | 150 m | full sensitivity above 400 m |
| Measuring range | 15 km | adjustable (7.5-30 km) |
| Range resolution | 30 m | adjustable (15, 30, or 60 m) |
| Antenna beam width | 0.6° | |
| Doppler velocity resolution | 0.025 m/s | depends on FFT length |
| Maximum unambiguous velocity | ±20 m/s | |
| Maximum sensitivity at 5 km (integration 0.1 s) | -45 dBZ | |
| Calibration system accuracy | ±0.5 dB | |
| Number of gates (with simultaneous stored raw data) | 500 | |
| Number of averaging spectra | 200 | adjustable (1-32768) |
| Manufacturer | Metek |