Micro Rain Radar

A vertical pointing microwave profiler reporting rain rate, liquid water content and drop size distribution
Biral mrr3
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The Micro Rain Radar (MRR) is a vertical pointing microwave profiler for the measurement of rain rate, liquid water content and drop size distribution from near ground to several hundred metres.

Applications include:

  • Observation of the melting layer (bright band / freezing layer)
  • Drop size distribution
  • Now-casting of precipitation events
  • Weather radar signal adjustment
  • Hydrology / precipitation studies
  • Cloud physics studies
  • Rain measurements on ships and platforms
  • Chemistry changes through precipitation transport

Technical Description

The unique and innovative Micro Rain Radar (MRR) is a small, portable and easy to operate. It can be used for now-casting of precipitation i.e., it will detect the start of rain from ground level to high above the radar several minutes before the start of rain at ground level.

It is a highly reliable system suitable for use in remote and extreme environments, requiring minimal maintenance and is well adapted for long term unattended operation.

Statistically stable drop size distributions can be derived within a few seconds due to the size of the scattering volume. The Micro Rain Radar (MRR) can detect very small amounts of precipitation (below the threshold of conventional rain gauges) detecting drop sizes between 0.25 mm and 4.53 mm. This covers the size range of atmospheric precipitation drops as larger drops in the atmosphere are affected by the air resistance as they fall and will split into smaller drops.

The droplet number concentration in each drop-diameter bin is derived from the backscatter intensity in each corresponding frequency bin. In this procedure the relation between terminal falling velocity and drop size is exploited.

The data is available in raw data format, last data set, averaged data set and other modes. The accompanying software package allows you to control the settings, visualise the data, print it

and export it to other applications for viewing, publication and storage etc.


  • vertical profiles of rain rate and liquid water content up to 6 km (3.7 miles)
  • computes detailed drop size and distribution output
  • user adjustable averaging intervals and height resolution
  • very low maintenance
  • high system reliability
  • remote/ long term unattended operation
  • high quality measurements
  • no wind, sea spray or evaporation induced errors
  • adjustable averaging intervals 10 – 3600 s
  • height range steps between 10 m to 200 m (600 ft) with 30 range gates
  • battery or mains power



The MRR is supplied with a comprehensive software package for instrument control, data logging and visualisation.

Frequency permission and operation of the MRR

The customer / end user is liable for the acquisition of the frequency permission and the operation of the MRR system for the region of use. Biral can provide guidance to users in acquiring permission.


Transmit power
50 mW
24.23 GHz
Sampling time
10 s
Averaging interval - adjustable
10 - 3600 s
Height resolution (steps) - adjustable
10 - 200 m
Lowest usable measuring height:
2 height steps
Number of height steps (range gates) - adjustable
up to 30
Accuracy for 1 min average
1/100 mm/h
Modulation type:
saw tooth
depends on adjusted height resolution ie:
1.5 MHz for 100 m height steps
3 MHz for 50 m height steps
Power supply
mains (100 - 240 VAC) or 24 VDC available as standard
Power consumption
25 W @ 24 VDC
Radiated Power
50 mW
6 kg
Software for online control, data visualisation, transfer and storage
MRR control software + MRR graphics program
Cable - data and power
25 m
Data transmission interface
RS232 or RS422
Automatic restart after power breakdown with no loss of settings

Sales & Support

Contact Biral for more information

To find out more about this instrument or to discuss your application requirements please do not hesitate to contact Biral.

After Sales Support

Biral offers free advice and technical support for the lifetime of the instruments we sell. Once you have purchased the unit you can always contact us for help using the links on our Service Support page.

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