Air Currents in a Mountain Valley Deduced From the Breakup of a Stratus Deck

Abstract

A sequence of aerial photographs is presented that illustrates the breakup of a stratus deck that filled the Redwood Creek Valley in northern California on Nov. 4, 1971. The vertical circulation within the valley was deduced from the breakup of the deck: air was rising along the sides of the valley, air was sinking along the center of the valley, and air was moving diagonally away from the center of the valley in a downstream direction connecting the rising and sinking air. This circulation has been suggested in theory, and the rising and diagonal components have been observed. The sinking component, however, has not been observed. The stratus breakup presented in this paper is submitted as evidence that the sinking component exists.