The new cloud droplet probe, from Droplet Measurement Technologies, has angled tips to deflect particles away from the beam path and minimize the effects of “forward scattering.”
The new cloud droplet probe, from Droplet Measurement Technologies, has angled tips to deflect particles away from the beam path and minimize the effects of “forward scattering.”
Kicking off the new fiscal year, on October 1 the ARM Aerial Facility received the first component - a cloud droplet probe (CDP) – of many new aircraft research instruments that will arrive in the coming year through funding from the American Recovery and Reinvestment Act.
Designed to measure the size distribution of cloud particles, the new probe incorporates an upgraded design and electronics to minimize the effects of "forwarded scattering," or shattering of ice crystals, that scientists believe may be causing erroneous measurements. The new cloud probe was immediately shipped to Stratton Park Engineering Company and is being installed on their Learjet 25 for the upcoming Small Particles in Cirrus (SPARTICUS) field campaign. During this campaign, data from the new probe will be used to help address the shattering issue, which has significant implications for cloud data used in climate modeling.

Chosen not only for its measurement capabilities but also flexibility, the new probe is planned to be part of a combined instrument, the cloud spectrometer and impactor (CSI). While the CDP measures the size distribution of particles, the impactor component measures the total water content – both liquid and ice - of the particles. When used together, the combined CSI instrument provides more complete information about cloud properties. Once the SPARTICUS field campaign concludes in the spring, the CDP will be added to the “impactor” part of the instrument which is scheduled to arrive around that time. The CSI will then be available for future aircraft campaigns.

The new probe represents the first arrival of six new cloud probes slated to enhance the AAF through funding from the Recovery Act. Nearly a dozen more AAF instruments for measuring aerosols, gases, and atmospheric state parameters will be received in the coming year through Recovery Act funding.