I've been trying to understand the Coriolis effect on the Earth's surface. The general equations produce two terms: The first is R'' and the second is 2ΩxV, where R is the position of the point on the Earth's surface, V is the velocity (relative to Earth) and Ω = ωk. Where ω is the Earth's angular velocity. In the book I'm using, the R'' term is neglected as it is too small, being of the order ω^2R and the focus is on the second (Coriolis) term. However, this is of the order of ω. By my calculations w^2R is about 0.03 (ω = 7 X 10^-5 and R = 6.4 X 10^7m). Even after resolving R'' into a component parallel to gravity, the residual component is still bigger than the Coriolis component. I'm a bit stuck as why the apparently larger component is the one neglected. Does anyone have any ideas?