Nick,
This thread was initially about 'Autorotation and Ground-Effect'. As part of this discussion, the 'effects' of the ground were considered. This thread then moved on to consider the 'causes' of ground effect.
There is obviously a distinction between 'Cause' and 'Effect'.
I politely suggest that;
*~ Your mentioning of; reduced angle of attack, reduced drag, and reduced power, are actually part of the 'Effect'. They are not part of the 'Cause'.
* ~ You deny that pressure is a 'Cause' of ground effect. I submitted the previous web page because it very clearly presents the relationship that exists between an airfoil and pressure, and by extension between, an airfoil, pressure and the ground.
____________________
There is probably no definitive answer, and as you say, this thread may have run its course, but, if you wish to continue, it will be appreciated if you attack the subject and not the person.
Yours truly;
Lu
oops Dave J.
