The Role of Generating Cells in Natural Ice Production and Supercooled Liquid Water Depletion

Conceptual models for glaciogenic cloud seeding techniques involve the conversion of supercooled liquid water (SLW) into ice and snow. In order to understand and evaluate glaciogenic cloud seeding, it is important to understand the natural behavior of the cloud with regard to its production of SLW. The production of ice, whether from natural sources or glaciogenic cloud seeding techniques, is known to deplete SLW and is therefore the basis for the conceptual model of how glaciogenic cloud seeding can initiate and enhance precipitation formation in clouds. However, what is less clear is the role that natural ice plays in the effectiveness of glaciogenic cloud seeding. During the Seeded and Natural Orographic Wintertime clouds: the Idaho Experiment (SNOWIE) field campaign, generating cells were frequently observed in the very high-resolution W-band airborne cloud radar data. These generating cells are thought to be the focal points for ice initiation in clouds that otherwise are generally ice-free. This abstract examines several cases from SNOWIE that exhibited generating cells structures, focusing on the in situ measurements inside and outside these cells, as well as contrasting to a case without generating cells. The goal of this study is to better understand the sources of natural ice formation, in order to investigate the impacts of glaciogenic cloud seeding on winter orographic clouds.