Laser Disdrometers

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The laser disdrometers are is a surface-based laser-optical systems conceived to measure simultaneously size and fall speed of hydrometeors passing through a laser matrix. They are affordable systems characterized by limited mainteinance and easyness of deployment. The systems at ISAC, Roma are produced by OTT and are named PARSIVEL (PARticle SIze and VELocity) and PARSIVEL 2, the latter one featuring a better quality laser allowing a higher sensitivity in measuring hydrometer type and size distributions. The instrument simultaneously measures particle size from 0.3 to 30 mm diameter and fall speed up to 20 m/s. By representing particles in a size-fall speed domain permits classification of each particle into one of several hydrometeor types such as hail, rain, drizzle, graupel, snow, and rimed or melting particles. Typically the two systems are installed in the roof of the ISAC building in Rome. The older one is providing long term measurements since 2010 to build valuable database for a climatological description of DSDs in the area of Rome. The PARSIVEL 2 is frequently moved to be used in sinergy with other precipitation measurement devices, including the Polar 55C weather radar