function [E, Ep] = eskew(u)
% ESKEW - Skewness and normalized skewness
% [E, Ep ] = eskew( u )
% Eqns. 1 and 2 in Wright et al., 1994 Marine Geology 118:67-77.
up = u-mean(u);
E = mean( up.^2 .* up );
Ep = E /  (mean(up.^2)).^(3/2);