A Transformational Approach to Winter Orographic Weather Modification Research: The SNOWIE Project

Abstract

The Seeded and Natural Orographic Wintertime Clouds: The Idaho Experiment (SNOWIE) project aims to study the impacts of cloud seeding on winter orographic clouds. The field campaign took place in Idaho between 7 January and 17 March 2017 and employed a comprehensive suite of instrumentation, including ground-based radars and airborne sensors, to collect in situ and remotely sensed data in and around clouds containing supercooled liquid water before and after seeding with silver iodide aerosol particles. The seeding material was released primarily by an aircraft. It was hypothesized that the dispersal of the seeding material from aircraft would produce zigzag lines of silver iodide as it dispersed downwind. In several cases, unambiguous zigzag lines of reflectivity were detected by radar, and in situ measurements within these lines have been examined to determine the microphysical response of the cloud to seeding. The measurements from SNOWIE aim to address long-standing questions about the efficacy of cloud seeding, starting with documenting the physical chain of events following seeding. The data will also be used to evaluate and improve computer modeling parameterizations, including a new cloud-seeding parameterization designed to further evaluate and quantify the impacts of cloud seeding.

Decoupling between Precipitation Processes and Mountain Wave Induced Circulations Observed with a Vertically Pointing K-Band Doppler Radar

“…Recent results from the SNOWIE field campaign about winter orographic clouds and precipitation [48] found a frequent decoupling between the orographic cloud layer where precipitation was formed and the near-surface air layer, which was trapped at the bottom of the valley. In our study, we also find a decoupling between ground-level conditions and higher levels but affecting precipitation profiles as well.…”

Detailed Dual-Doppler Structure of Kelvin–Helmholtz Waves from an Airborne Profiling Radar over Complex Terrain. Part I: Dynamic Structure

“…The SNOWIE and CAMPS campaigns Data for this study were drawn from two field campaigns, both set in the intramountain, western United States. The first and most recent project, Seeded and Natural Orographic Wintertime Clouds: The Idaho Experiment (SNOWIE), was launched in order to address questions pertaining to both natural and seeded orographic clouds (Tessendorf et al 2019). SNOWIE took place between 7 January and 17 March 2017 in the Payette basin northeast of Boise, Idaho (Fig.…”

“…1a). Tessendorf et al (2019) describe the complete SNOWIE experimental design, project domain, and observed cloud and precipitation properties. The experimental design did not consider KH waves; their prevalence in all stratiform precipitation systems sampled during SNOWIE came as a surprise, and led to the questions that motivated this study.…”

Evaluation of the Wyoming Weather Modification Pilot Project (WWMPP) Using Two Approaches: Traditional Statistics and Ensemble Modeling

“…The various seeded ensemble members investigated here attempt to capture this uncertainty, recognizing that more research is needed to have full confidence in the scheme. The recent Seeded and Natural Orographic Wintertime Clouds: The Idaho Experiment (SNOWIE) project (French et al 2018;Tessendorf et al 2018) was largely motivated to reduce this uncertainty, and data from this field program is currently being analyzed and used to evaluate and improve the seeding algorithm.…”

“…This would require specific field studies for both ground and airborne seeding. The recent SNOWIE field effort (Tessendorf et al 2018;French et al 2018) has provided an excellent dataset for such an evaluation.…”