In Europe, Eurocode EN1991-1-4:2004 describes wind loads. The nominal pressure (characeristic peak velocity pressure) for a wind with speed $v$ is calculated as
$$q = \frac{1}{2} \rho v^2$$
where:
- $\rho$ is the air density.
- $v$ is the velocity when taking into account orography and roughness.
Section 7 is devoted to pressure and force coefficients. It states net pressure coefficients should be determined for free standing wall and fences and monopitch canopies and monopitch roofs.
Additionally, it defines friction coefficients for forces parallel to the surface.
Without any data, I can't really provide much further guidance because most of the data in the standard its in tabulated form.