Curvature effects in EM scattering from ocean surface are described using a generalized curvature expansion of the fields at an elevated nonperfect conducting surface. The new expansion formalism allows us to describe analytically and in general, without separating into different scales, the scattering of EM waves from an undulated ocean surface. The model is exact to first order in curvature for nonshadowing imaging geometry, and obeys
the law of reciprocity and tilt invariance. Explicit expressions for EM fields at the surface, including both the projection and the self induced fields, are derived up to first order in surface curvature. Analytic closed form expressions for the scattered fields are derived from the surface field solutions, and applied to the case of backscattering, providing a general expression for the normalized radar cross section. The analytic expression for the normalized radar cross section is implemented for a linear surface model using both the Eulerian and the Lagrangian fr