Deep Valley Radiation and Surface Energy Budget Microclimates. Part I: Radiation

Abstract Solar and longwave radiation data are presented for five sites in Colorado's 650 m deep semiarid Brush Creek Valley (39°32′N, 108°24′W) during September 1984. During the sunlit period of a nearly clear day, individual sites received 0.73–0.81 of the theoretical extraterrestrial solar radiation. Incoming solar radiation increased with elevation in the valley. Direct radiation made up 0.86– 0.88 of the downward shortwave flux. On average, 0.12–0.21 of the incoming shortwave radiation was reflected at the individual sites. Strong variations in reflected solar radiation and outgoing longwave radiation occurred from site to site. Because of the large direct beam component, aspect and inclination angles of the valley surfaces had a strong effect on the solar radiation received. Contrasts between a southwest- and northeast-facing sidewall were significant. Shading from surrounding topography produced inter-site differences in both instantaneous and daily total radiation. Inter-site differences in most d...