A miniature oscillating microbalance for sampling ice and volcanic ash from a small airborne platform

摘要

A lightweight and low power oscillating microbalance for in situ sampling of atmospheric ice and volcanic ashudis described, for airborne platforms. Using a freely-exposed collecting wire fixed at only one end to a piezoudtransducer, the instrument collects airborne material. Accumulated mass is determined from change in naturaludfrequency of the wire. The piezo transducer is used in a dual mode to both drive and detect the oscillation.udThree independent frequency measurement techniques are implemented with an on-board microcontroller:uda frequency sweep, a Fourier spectral method, and a phase-locked loop. These showed agreement to ±0.3udHz for a 0.5 mm diameter collecting wire 120 mm long, flown to 19 km altitude on a weather balloon. Theudinstrument is well suited to disposable use with meteorological radiosondes, to provide high resolution vertical profiles of mass concentration.