Numerical simulation of cross-valley plume dispersion during the morning transition period

Abstract

In the summer case, the lower plume migrated to the more strongly heated southwest sidewall in the first 90 min after sunrise, and was then advected up the sidewall in the slope flow for the remainder of the simulation. The upper plume diffused slowly in the remnants of the nocturnal inversion layer until it was entrained by the growing convective boundary layer 3 h after sunrise. The boundary layer's thermodynamic structure remained nearly symmetric about the valley axis throughout the transition period. The asymmetric dispersion characteristics seen in the summer case were not found in the winter simulation. -from Authors