page_title: Millimeter cloud radar
section_title: Measurement example
hierarchical_section_title: Millimeter cloud radar / Measurement example
caption_attribution_description: English: Measurements performed by a MIRA36 system in Tito Scalo, Potenza (Italy) on 2nd December 2014: (a) equivalent reflectivity, (b) Linear Depolarization Ratio, (c) Doppler velocity, where negative values indicate movement towards the radar, and (d) peak width.
context_page_description: Millimeter-wave cloud radars, also denominated cloud radars, are radar systems designed to monitor clouds with operating frequencies between 24 and 110 GHz. Accordingly, their wavelengths range from 1 mm to 1.11 cm, about ten times shorter than those used in conventional S band radars such as NEXRAD.
context_section_description: As the cloud radars sample the atmosphere, they measure the backscatter signal produced by different hydrometeor types (cloud droplets, drizzle, rain drops, ice particles, snow, etc.) and non-hydrometeorological targets. All these targets have different vertical velocities and shapes, and therefore the Doppler spectra and LDR can be used to distinguish between targets. In the figure below, an example of the MIRA-36 cloud radar measurements in Potenza is shown, where using the information given by the different parameters, an identification of targets can be done:
  Liquid water clouds produce a signature in the reflectivity but not in the LDR, since the liquid droplets are almost spherical.
  Ice clouds are characterized by relatively high LDR signals due to their irregular shapes.
  Insects produce high LDR values and are usually within the Convective Boundary Layer (CBL), where up- and downdrafts are observed continuously.
  The melting layer can be identified by an enhancement of the LDR, which is caused by irregular ice particles coated by liquid water during the phase transition.
  Rain is characterized by high reflectivity values, high falling velocities and a broadening of the spectra.
  Liquid layers within  mixed-phase clouds can be detected by slightly higher peak width values, in accordance to the higher turbulence within.
caption: Measurements performed by a MIRA-36 system in Tito Scalo, Potenza (Italy) on 2 December 2014: (a) equivalent reflectivity, (b) Linear Depolarization Ratio, (c) Doppler velocity, where negative values indicate movement towards the radar, and (d) peak width.
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