A new description for multiscale surface roughness containing all frequencies above a minimum value has been developed. Analytic equations for autocorrelation functions are given to surfaces with Gaussian, exponential, isotropic exponential and transformed exponential multiscale surface correlations. A method for applying these autocorrelation functions to surfaces rough only in separate frequency bands is also presented. The obtained multiscale exponential autocorrelation function fits well to measured 1 m-50 m long profiles of Baltic sea ice. The surface description is also combined with the Integral Equation Method for calculating the surface backscattering coefficient and applied to Baltic sea ice. However, the validity of approximating the local incidence angles with the radar incidence angle, typically used in IEM calculations, was seriously limited by the small permittivity of ice. Reliable estimation of the field coefficients requires further investigation.