If anyone has obtained aviation weather for a particular airfield, they know that winds at the surface vary in direction and magnitude from the winds aloft, and winds aloft vary at differing elevations, with mixing between layers.
The jet stream is called a stream for good reason, and weather uses many of the same descriptors such as troughs, ridges, depressions, etc, just as landforms (both continental and oceanic) have troughs, ridges, depressions, etc, which affect the flow of the respective overlying fluids.
As Boats mentioned, distant conditions affect local conditions.
Winds aloft over two distant airfields may be quite similar, but winds at the surface may be different because of the respective local terrain conditions.
Airfoils are considered to be relatively smooth surfaces (excluding rivets, stitching, taping, other imperfections, etc) but depending on the amount of camber (curvature) of the upper and lower surfaces (which often differ), for given velocities, flow over the surfaces may be laminar, or (as airspeed and angle of attack change) flow may separate from the surfaces creating turbulence, vortices, drag.
Local landforms vary in the amount of curvature and surface roughness, height, orientation to oncoming wind, angle of slopes, etc, which affect localized airflow.
Surface roughness will vary by vegetation type as well.
I'd love to see joeb post a simple list of all the variables that affect airflow,
before the variables were entered into any spreadsheet.
joeb wrote Quote:The ELEY and LAPUA tunnels are doing it wrong! Also, the entire warehouse business is incorrect! Fill in them tunnels, tear down them warehouses, get out in the wind!
(There are more noodles visible than I've ever imagined.)
joeb,
Don’t those tunnels have ventilation?
Doesn’t ventilation require airflow?
Have you ever considered taking a geomorphology class, and maybe an aviation weather class too?