https://doi.org/10.1016/j.atmosres.2025.108330

Orography can disturb atmospheric flow fields by affecting the flows's interactions with precipitating particles. Turbulence influences localized flow patterns and impacts the meteorological conditions at the surface and aloft. This study aims to characterize the origin of turbulence prior to and during precipitation events. Automatic measurements were collected at two different elevations in the south-eastern Canadian Rockies: Fortress Junction Station (FJS) in the valley (1591 m MSL) and Fortress Powerline Station (FPS) at a higher elevation (2076 m MSL). Doppler lidars collected measurements for high-precision (spatial and temporal) atmospheric motion, three-dimensional wind fields, planetary boundary layer (PBL) properties, cloud, and precipitation layers. The turbulence origin and intensity of the fine-scale flow were characterized. We conducted an in-depth investigation of one event associated with heavy precipitation and compared the data from that event with a clear-sky reference day. Data reveals higher wind variability and turbulence at the high elevation site (FPS), with a thicker PBL and more solid hydrometeor compared to the lower elevation site (FJS). The turbulence originated either from surface heating, cooling from aloft, or hydrometeor phase change depending on the time of day, altitude, and atmospheric conditions. Overall, this study provides new experimental observations of the interactions between fine-scale flow fields, small scale turbulence processes, and precipitation in the Canadian Rockies.

https://doi.org/10.1016/j.atmosres.2025.108330