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Micro Rain Radar

JOYCE-JOYRAD35 ©B. Pospichal
Micro Rain Radar installed at Jülich


The Micro Rain Radar (MRR) is a vertical pointing FM-CW (frequency modulated –continuous wave) Doppler radar operating at 24.1 GHz (K-band, 12.4 mm wavelength). The emitted radar signal (only 50 mW transmitting power) is backscattered by falling hydrometeors (rain, graupel, snow). From the Doppler spectra the radar reflectivity factor (Ze) and the terminal fall velocity distribution can be derived.

In case of rain the Doppler spectra can be used to derive vertical profiles of microphysical rain properties like drop size distribution and rain rate.

The MRR system was also studied for its potential to observe snowfall (Kneifel et al., 2011). Also, an improved MRR algorithm IMProToo most suitable for snowfall observations has been developed at IGMK (Maahn and Kollias, 2012). It is freely available on Github.

Measurement modes

  • Vertically pointing observations with integration times from 10 to 3600 seconds.
  • The range resolution can be varied from 10 to 200 m which determines together with the 30 range gates the system's maximum height range of 300 to 6000 m.

JOYCE-CF Standard Operation Procedures

  • Temporal resolution 10 seconds
  • Vertical resolution 35 meters (max. range = 1085 m)

Calibrations and data quality assurance procedures

  • ImProToo features a noise removal based on recognition of the most significant peak and a dynamic dealiasing routine which allows observations even if the Nyquist velocity range is exceeded.

Data availability

Data are available on request, please fill the data request sheet and send it to

Dataset Temporal resolution File size Filename Remarks
Raw data (ASCII) 10 seconds 1 file per day (~15 MB) YYYYMMDD_jue_mrr_raw_txt.gz METEK format (zipped)
IMProToo (NetCDF) 1 minute 1 file per day (20-30 MB) IMProToo product (zipped)

Both available datasets include Doppler spectra, drop spectra, radar reflectivity, rain rate, and fall velocity.

Data quicklooks can be found in the JOYCE quicklook browser.

Measurement examples

MRR_IMProToo Rain_rate
Example time series of MRR observations (left: IMProToo radar reflectivity, spectral width, rain rate and mean spectral noise / right: rain rates from MRR (bottom), compared to Parsivel and Pluvio)

MRR History

Period Place Project
03/2012 - today Research Centre Jülich TR32
04/2008 - 10/2011 Selhausen, Germany TR32
05 - 12/2007 Heselbach, Blackforest, Germany COPS
2006 - 2007 Nangatchori, Benin AMMA

Technical Specifications

Parameter Specification
Frequency 24.1 GHz
Wavel 12.4 mm
Radar Type FM-CW
Transmit Power 50 mW
Receiver Single Polarization
Power consumption (radar) 25 W
Total power cons. incl heating 525 W
Max. range 6 km
Range Resolution 10-200 m
No. of range gates 30
Temporal resolution 10 s
Antenna diameter 0.5 m
Beam width (2-way, 6 dB) 1.5°
Manufacturer Metek
mrr.txt · Last modified: 2021/03/01 11:17 by bpospich