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This study provides a description of scatterplate interferometry from both a theoretical and experimental viewpoint. Although this interferometer is a relatively simple and very effective device for use in the optical shop, very little beyond a qualitative description has been previously presented. Through the use of Fourier optics and stochastic processes techniques, a more formalized theory of scatterplate interferometry is shown particularly in how the flip or inversion symmetry of the scatterplate itself affects the flip symmetry. Also described are the effects on the fringe quality produced by non laser sources as well as aberrations in the interferometer optics. Experimental verification of these aspects is shown to be in good agreement with the theory. Of interest to the shop user of this interferometer is the material presented on scatterplate fabrication. Techniques for making the conventional, "double-exposure" or "180°-type" scatterplate, are very simple to those with access to a holography lab. Additional refinements including null testing with the scatterplate and an infrared scatterplate interferometer are also described.

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No description available.

No description available.

No description available.

No description available.

No description available.

The energy balance of the Earth is regulated in part by ice clouds, which both reflect shortwave solar radiation and absorb infrared radiation from the Earth. These clouds appear frequently worldwide, with up to 70% coverage in tropical regions. The microphysics of ice clouds determines their radiative properties, and is important for accurately predicting the role of ice clouds in Earth’s energy balance. However, describing the microphysics of ice clouds remains a challenging problem, especially with regard to the shape of ice particles and the degree of ice particle surface roughening. In-situ studies have found evidence for ice surface roughness and have found many complex ice geometries; however, these studies are limited spatially and temporally. An approach which allows large-scale analysis is to retrieve these properties via theoretical modeling using satellite observations of polarized reflectance from ice clouds, since polarized reflectance is sensitive to the shape and roughness of ice particles. The theoretical model requires the scattering properties of simulated ice particles. These properties are obtained for 10 different ice shapes and 17 different levels of surface roughness. Simulations are performed for 3 different effective ice particle diameters: 30, 60 and 90 μm. Overall, the retrieved shape is dominated by the compact aggregate of columns. Although the exact composition of shapes varies from month to month, the compact aggregate of columns remains the most commonly retrieved shape. The retrieved roughness varies from moderately rough at σ = 0.1 to severely rough at σ = 0.5. Retrieved roughness varies more than shape, and smooth surfaced ice is most prominent in January. Tropical regions tend to have ice particles that are more roughened, while the midlatitudes and polar regions tend to have more smooth ice. In almost all cases, roughened ice represents > 60% of the total retrievals. The asymmetry parameter inferred from the retrieval of ice particle shape and roughness has a mean value near 0.77, with only small differences based on assumed ice effective diameter. The median value of the asymmetry parameter has a nearly constant value of approximately 0.75.