Mesa Photonics’ Cloud Droplet Measurement System (CDMS) implements a compact optical imaging technology for in situ measurement of cloud droplet size distribution function and droplet number density in the size range of 10–1000 µm. The method is based on analysis of scattered light images of individual droplets from an image frame containing images of multiple droplets illuminated by a sheet-shaped light source. The instrument is equipped with a wireless telecommunication system that broadcasts the data to the ground station. The data can also be stored on a local hard drive. The preferred deployment platform is tethered balloon system (TBS).
Atmospheric measurement instrumentation needs to be calibrated in the field. Mesa Photonics’ Portable Monodisperse Droplet Generator (PMDG) is a compact battery-powered instrument that generates a jet of fixed-size monodisperse droplets. The PMDG is ideal for field calibration of in situ cloud probes and precipitation measurement instruments.
The CDMS implements a compact optical imaging technology for in situ measurement of cloud droplet size distribution function and droplet number concentration. The method is based on analysis of scattered light images acquired at 90-degree scattering angle from multiple individual droplets illuminated by a sheet-shaped, pulsed, spectrally broadband (“white”) light source. White light illumination mitigates the ambiguity of the inverse Mie scattering problem of obtaining the particle size from the scattered light intensity. The droplet/drizzle diameter measurement range is 10-1000 micrometers; the droplet number density is up to several hundred per cubic centimeter. The CDMS has dimensions of 12 in. x 12 in. x 4 in.; it weighs less than 7 pounds (including battery) and draws less than 30 W of electrical power. The instrument is equipped with a wireless telecommunication system that broadcasts the data to the ground station. The data can also be stored on a local hard drive. The main application is in situ characterization of droplets in atmospheric clouds. The preferred deployment platform is tethered balloon system (TBS).
Technical Specifications (preliminary)
Portable Monodisperse Droplet Generator (PMDG) is a compact battery-powered instrument that generates a jet of fixed-sized monodisperse droplets. The principle of operation is based on disintegration of a cylindrical liquid jet caused by periodic disturbance applied to the jet, which makes it dynamically unstable under the action of surface tension — this effect is commonly referred to as Savart–Plateau–Rayleigh instability of a liquid column. The PMDG is ideal for field calibration of atmospheric measurement instrumentation such as in situ cloud probes and precipitation measurement instruments. The PMDG has recently been used to field calibrate the Mesa Photonics’ tethered-balloon-based Cloud Droplet Measurement System (CDMS). The current version of PMDG produces a jet of monodisperse droplets 193 µm in diameter; the instrument weighs 25 lbs and has dimensions of 21″ x 13″ x 7.5″. The power draw is 12 W; the battery operation time is about 5 h.
Technical Specifications (preliminary)