Ocean surface, is an example of a field that can be considered as a 2 dimensional random field that evolves in time. In fields like these, we can consider questions related to excursion sets lying in the plane. The geometry of these sets is naturally quite complex, and in order to study it properly we shall need to delve into the subject of integral geometry. We will investigate what kind of preconditions we need to place on our mathematical models to ensure that objects like contour lines are disjoint smooth twice differential curves. We will also present a generalization of the Rice formula, that allows us to count points on these contour lines, that satisfy certain conditions. With this tool at hand, we will finally calculate the mean value of the integral characteristic and indicate how this is used in our work on velocities for random fields.