A Particle Phase Spectrometer for Cloud Microphysics Research

Satellite microphysics retrievals rely on in situ measurements to tune and validate their algorithms. Particle imaging probes have been the most reliable in situ instruments for identifying the shapes of cloud particles, thereby distinguishing (non-spherical) ice particles from (spherical) water drops. However, improvements in the pixel resolution, number of gray-levels and software processing of the particle images are required to take these measurements to the next level. Here we describe a new optical probe that vastly improves the ability to automatically identify and classify ice particles and water drops in mixed-phase clouds. The Particle Phase Spectrometer that SPEC will design and test in the laboratory in Phase I will integrate three optical instruments into a single package: 1) a very high-resolution (1-mu;m pixel resolution) digital camera imaging system, 2) a 10-mu;m 2D-Gray optical array probe and 3) a forward scattering probe that sizes particles from 2 to 50 mu;m.nbsp; The Particle Phase Spectrometer will provide unprecedented, high-resolution digital images that will be capable of distinguishing spherical from non-spherical cloud particles as small as 10 microns.nbsp;