UCASS weights 280 g and has been designed for combined use with a radiosonde, as a dropsonde, or as part of a UAV measurement platform. In contrast to conventional OPCs, the UCASS OPC features an open-path geometry that prevents particle losses and droplet shattering by the inlet that would need to be corrected for during data analysis [Smith et al.,2019]. The UCASS can be used for the measurement of aerosols or water droplets.
It can measure aerosol particles in the size range from 0.4 to 40.0 μmindiameter.As described in Smith et al. , the UCASS operates with a 658-nm diode laser and collects light scattered by individual particles in an angular range between 16°and 104°. Its operating principle is that aerosols pass through a shaped laser beam,cause a pulse of light to fall on an elliptical mirror from where it is directed onto the detector. Spherical-shaped particles (Mie scattering) are considered and a refractive index equal to 1.52+0.001i for dust particles(given by the manufacturer).