New Hotplate Technologies for Precision Measurement of Winds and Hydrometeor Mass, Density, and Type

Two new technologies are presented developed by the University of Utah in collaboration with Particle Flux Analytics, Inc. that are providing new perspectives on atmospheric physics. The Differential Emissivity Imaging Disdrometer (DEID) and the SnowPixel are two hotplate devices that operate with distinctive technologies. The DEID consists of a thermal camera that points at a single 7 cm x 7 cm aluminum hot plate with a low emissivity top surface. By exploiting the contrasting thermal brightness of low emissivity metal and high emissivitiy water, and using heat transfer physics, the DEID is able to determine with high accuracy the microphysical properties of hydrometeors at sampling frequencies up to 0.5-1 Hz and with masses and sizes greater than 0.01 mg and 50 µm respectively with resolution limited by primarily by the thermal camera resolution. The DEID has been used successfully to measure individual hydrometeor mass, density, and size, and bulk precipitation rates, snow water equivalent (SWE) rates, visibility reductions by precipitation, and predict fresh-snow avalanche onset when used in combination with a snowpack model.

The SnowPixel is a also a hotplate technology but it uses advanced micro-electromechanical systems (MEMS) fabrication techniques for the construction of a 24 x 24 array of individually controlled 0.5 x 0.5 x 0.01 mm platinum micro-heaters. Maintaining the 576 heaters at a temperature above the boiling point provides a high-resolution “video image” of atmospheric thermodynamic signatures. Preliminary analyses in snowy and windy environments are demonstrating that with signal analysis, statistics for the mass, frequency, and microstructure of individual snow and rain particles, precipitation rate and type, and the direction and speed of wind gusts. Thus, the SnowPixel suggests the potential for development of a miniaturized automated weather station for distribution in densely networked arrays for the weather, agricultural, insurance, military, and transportation safety sectors