Three-View Cloud Particle Imager

Short Name or Variable Name
3V-CPI
  • The Three-View Cloud Particle Imager (3V-CPI) is a combination of three imaging instruments. Two of them comprise a 2D-S instrument, in which two 2D probes image particles as they pass through beams that are oriented orthogonally to each other and the airflow. If particles also lie in the intersection of the sensitive areas of the two beams, they are seen by both 2D probes. In that case, the CPI is triggered to take a high-resolution picture, via a briefly illuminated high-resolution imaging array, to provide a third image at high resolution. The optical arrangement is illustrated in the following figure:

    • The 3V-CPI mounted on a C-130 pod (left), and on a pylon under the GV wing with a protective shroud (right)

3V-CPI has flown on both the GV and C-130, as pictured above. The probe is particularly suited to imaging ice crystals, but also provides good detection of other hydrometeors including large cloud droplets, drizzle and small rain drops, and precipitation particles.

Calibration Methods

Size calibration is checked with a spinning disk (a disk with images on it that is rotated rapidly through the sensing volume). Optical alignment is also needed but is a specialized process best done only occasionally.

Primary External Contacts
Paul Lawson, SPEC
Lead Contact
Sarah Woods