Vertical Motions in Orographic Cloud Systems over the Payette River Basin of Idaho: results from SNOWIE
The Seeded and Natural Orographic Wintertime Clouds: the Idaho Experiment (SNOWIE; Tessendorf et al. 2019) occurred between 7 January and 16 March 2017 and provided new insight into vertical motion magnitudes and distributions and their effect on precipitation and microphysical properties over the Payette River Basin of Idaho. As part of this analysis, Zaremba et al. (2022a; Part 1) developed methodology to retrieve vertical air velocity and flight leg averaged particle terminal velocity profiles from airborne radial velocity measurements and assessed the validity of vertical motion retrievals. Using this retrieval methodology, vertical motions over the Payette River Basin could be separated and characterized into two groups, the first forced by the orography and fixed in space relative to the mountain slopes (stationary waves), and the second transient, triggered by vertical shear and instability within passing synoptic-scale cyclones (Zaremba et al. 2022b; Part 2). This work also assesses the impact of fixed and transient updrafts on the likely trajectories of seeded particles and found that transient vertical circulations minimally impact the distance particles generated by seeding travel and the landing elevation of particles with respect to the ideal target elevation (Heimes et al. 2022; Part 3). We are currently in the process of exploring the controls on liquid water content, drop number concentrations, and drop size distributions relative to fixed and transient vertical motions observed over the complex terrain of the Payette River Basin during SNOWIE (Zaremba et al. 2023, Part 4).
