Turbulence measurements for very stable conditions near the surface are contrasted
among three sites: a high altitude basin during winter with grass or snow-covered
grass, a broad valley with complex agricultural land use, and a more narrow valley that is
influenced by a valley cold pool and cold air drainage....
Turbulence quantities are analyzed from nine months of data collected on the floor of a valley where nocturnal cold pools are frequent. Often the speed of the vector-averaged wind over the night is less than 0.5 m s−1 (near-calm winds) with no preference for wind direction. The quantity of such...