I do not think I had "thermic help" over the hot concrete/pavement. I think the tall grass negated the ground effect.

On Friday, December 16, 2016 at 1:51:22 PM UTC-8, Charlie M. (UH & 002 owner/pilot) wrote:
I would sorta guess you had "thermic help" when over the pavement while you may have had sink over the grass.