Potential of Glaciogenic Seeding of Cold-Season Orographic Clouds in a Warming Climate

This presentation addresses how the operation of glaciogenic seeding of clouds over mountains in the Interior Western US will be impacted by climate change. We examine 10 years of regional climate model output in the retrospective (circa 2010) and future climate (circa 2060). The future climate represents conditions around ~2060 assuming the IPCC RCP8.5 scenario. The climate change is imposed on the retrospective boundary conditions using the Pseudo-Global Warming technique. Using the mountains in western Wyoming as an example, we look at how the factors impacting ground-based cloud seeding (mainly temperature, cloud liquid water path, and static stability, are impacted by climate change). We assess changes in blocking/unblocking frequencies by evaluating the Froude number. Since blocked flow requires seeding from an aircraft and unblocking allows the usage of a network of ground-based generators, cloud seeding techniques may need to be adapted for climate change. We use various temporal and spatial perspectives to evaluate changes in frequency of the relevant factors. Finally, to quantify changes in seeding impact in a warmer climate, we simulate seeding-induced vs. natural precipitation amount for one winter of actual ground-based seeding over the Wind River Range (2014-2015), and compare this to the same scenario in a warmer climate (50 years later).