Microstructural characterization of firn

In this paper, we use a scanning electron microscope (SEM) coupled with X‐ray spectroscopy and electron back‐scattered diffraction patterns to examine firn in cores retrieved by the United States International Trans‐Antarctic Scientific Expedition. From grain boundary grooves we were able to see where the previously existing snow crystals were joined, and can determine grain sizes. From the SEM images, the porosity and the surface area per unit volume of the pores were measured. Finally, we have shown that we can determine the microchemistry of impurities in firn and demonstrated that we can determine the orientations of the firn crystals. Copyright © 2007 John Wiley & Sons, Ltd.