Observations and Numerical Simulations of Winds within a Broad Forested Valley

Abstract

Abstract The Tennessee River Valley in the eastern part of Tennessee is a broad valley with a moist climate and extensive forest cover. A series of 50–100-m-high parallel ridges forms corrugations along the floor of the valley. Tower measurements and numerical simulations are used in this paper to study the channeling of the winds in this valley over the diurnal cycle. At night, pressure-driven channeling caused by geostrophic imbalances is often present, but this channeling tends to be concentrated on the leeward side of the valley (relative to the winds aloft). The channeling is significantly weaker during the afternoon, so the winds on top of the corrugations are more closely aligned with those aloft. In the bottomlands between the corrugations, however, the daytime winds are more effectively channeled parallel to the valley axis. Although thermally driven winds are not dominant in the Tennessee Valley, a discernible pattern of upvalley daytime winds and downvalley nighttime winds is observed in the to...