The Holographic Microphysics Imaging Extinctiometer (HoloMIE): A new cloud probe for characterizing cloud particles and measuring spectral extinction

Airborne measurements of cloud particle size, shape, and optical properties such as extinction cross-section are critical for furthering atmospheric science and advancing the use of satellite data to help understand the Earth system. The current generation of instruments cannot accurately characterize the shape and optical properties of particles smaller than 100 micro;m, especially in mixed-phase or glaciated conditions. We also lack tools for characterizing coarse mode aerosol, which are difficult to sample from aircraft, that can also have important atmospheric impacts. To address this shortcoming, we propose development of a holographic imaging system capable of single-particle or ensemble measurements depending on conditions and operator need. Benefits over current instrumentation include faster time resolution and better sampling statistics compared to existing holographic instruments, more detail regarding particle morphology compared to existing particle sizing and counting instruments, and better sampling characterization compared to imaging instruments. In addition, our technique will enable direct determination of extinction cross-section for individual particles under certain conditions, which will enable better measurements of aerosol and cloud extinction, especially for thin features such as sub-visible cirrus and aerosol layers.