The disdrometer (Drop Size Distribution meter) is an instrument capable of simultaneously detecting the size and fall rate of hydrometeors (e.g. water drops, snow, ice) that pass through its measuring area. Laser disdrometers are characterized by a sensor consisting of a laser matrix. They are low cost instruments (also in terms of maintenance), and they can be easily deployed and used as mobile instruments for measurement campaigns. The ISAC disdrometers are manufactured by OTT under the trade names PARSIVEL (PARticle SIze and VELocity) version 1 and 2. The second one has a better sensitivity for small droplet detection and has been configured to be easily installed to support measurement campaigns. When not used for such purposes it is installed on the roof of the ISAC in Rome. The older system has been working since 2010 at CIRAS and has allowed to build a first climatological database of precipitation DSD in the Rome area. Since 2018 the Parsivel version 1 is installed at the Antarctic station Mario Zucchelli. A Thies Clima laser dysdrometer by ARPA Piemonte is also available to ISAC.

Measured quantities: time series of the size distribution and fall speed of the hydrometeors in terms of equivalent diameters from 0.3 to 30 mm and fall speed up to 20 m/s.

Applications: Radar calibration, microphysics of precipitation, soil erosion.

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