investigation of top and bottom surface roughness was carried out on snow and ice thickness profiles sampled on 57 floes in the Ross, Amundsen, and Bellingshausen Seas between May and September 1995. An objective classification scheme was used to group the studied sea ice floes according to the degree of deformation they had undergone. Different roughness criteria and methods were applied to the classified floes. Roughness variances and other properties such as fractal dimensions, derived from Fourier spectra, depend critically on the deformational history of the floes under consideration. The wavelet transform is presented as a new, two-dimensional method to find dominant structure lengths and, at the same time, localize them in the studied profiles. Finally, air, water and ice surface drag coefficients are calculated from the surface roughness characteristics. Air drag coefficients ranged between 1.1 and 1.7¿103 and increased with increasingly deformed ice. ¿ 1999 American Geophysical Union