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Full-Text Articles in Physical Sciences and Mathematics
Laboratory Measurements Of Contact Nucleation By Mineral Dusts, Bacteria, And Soluble Salts, Joseph Niehaus
Laboratory Measurements Of Contact Nucleation By Mineral Dusts, Bacteria, And Soluble Salts, Joseph Niehaus
Dissertations, Master's Theses and Master's Reports
We present results from experiments that emulate atmospheric ice nucleation by aerosols. We have refined experimental techniques to improve measurements of ice forming nuclei in the contact mode. Our results show that atmospherically relevant dusts such as kaolinite, feldspar, rhyolitic ash, and Arizona Test Dust have efficiencies in the contact mode that are higher than the immersion mode. Experiments with bacteria show that biological material has the potential to contribute significantly to ice concentrations, but has large variability. By choosing a soluble compound as an ice nucleus, we are able to place bounds on the timescale for contact freezing and …
Testing Lidar-Radar Derived Drop Sizes Against In Situ Measurements, Mary Amanda Shaw
Testing Lidar-Radar Derived Drop Sizes Against In Situ Measurements, Mary Amanda Shaw
Dissertations, Master's Theses and Master's Reports
How well can a co-located lidar and radar retrieve a drop size distribution in drizzling clouds? To answer, we mimic scattering from a laboratory cloud to retrieve a lidar-radar effective diameter. Using only the shape parameter of the gamma-distributed drops, the mean diameter of the drops can be estimated from lidar-radar effective diameter to within a few percent of the true mean. In practice, the shape parameter of the gamma distribution is not known. To set bounds, mean diameters were calculated from the lidar-radar effective diameter using a range of in situ measured gamma shape parameters. The estimated means varied …