Area of Study
Science and Mathematics
It has been well documented that the reflective and diffusive properties of cirrus clouds influence the radiative budget of the earth; in turn, the surface morphology of cirrus ice crystals affects those properties. This summer work aimed to quantify the surface morphology of cirrus-like ice crystals grown in a Variable Pressure Scanning Electron Microscope (VP-SEM). The implementation of this goal occurred in two stages: crystals were first grown and imaged in the VP-SEM, then a Python code was developed to reconstruct a 3-dimensional model of the surface from the images. Crystals were grown at pressures between 50 and 100 Pa and imaged at the equilibrium temperature using the backscatter electron detector (BSE).
The Python code, which is still under development, uses a generalization of the Blinn-Phong shading model to determine the surface normal vector of each point in the images captured from the BSE detector. From the normal vectors, a raster surface profile is reconstructed. This code has not yet produced data for cirrus ice surfaces, due to the uncertainties in its reliability for reconstructing unknown surfaces. The code will be further developed as the subject a thesis.
Butterfield, Nick, "VP-SEM Investigation of 3-D Surface Morphology in Cirrus-like Ice Crystals" (2014). Summer Research. 213.
University of Puget Sound