Seminar

Abstract

Properly characterizing the sizes and concentrations of condensed water or ice is a fundamental goal in airborne cloud physics research. Measurement of small (less than about 150 microns) ice particles represents a particular challenge, due to the difficultly of capturing the form of the ice (for example when using optical techniques). The problem is further confounded by shattering of ice particles during sampling, which modifies the measured size distribution from what is present in the cloud by creating small particles from shattered large ice particles. Here, we present a summary of some techniques for addressing this problem, including a summary of recent instrumental approaches such as the small ice detector (SID II) to sample small ice and modification of the tips of instruments to reduce the shattering of large ice. A summary of some results from the recent Instrument Development and Education in Airborne Science (IDEAS) flight test program will be presented. During this program we tested a new instrument, HOLODEC II, which uses holography to reconstruct a three dimensional view of hydrometeors and offers a new approach to solving this problem. We also present an overview of current and planned instrument flight testing as part of the IDEAS program.