This INCITE project focuses on two science questions that can be answered with the ACME v1 model and DOE capability computing resources:
1. Water Cycle: How will more realistic portrayals of features important to the water cycle (resolution, clouds, aerosols, snowpack, river routing, land use) affect river flow and associated freshwater supplies at the watershed scale?
2. Cryosphere Systems: Could a dynamical instability in the Antarctic Ice Sheet be triggered within the next 40 years?
For the water cycle question, the team hypothesizes that changes in river flow over the last 40 years have been dominated primarily by land management, water management and climate change associated with aerosol forcing, but that during the next 40 years, increasing atmospheric greenhouse gas concentrations will produce changes to river flow with signatures that dominate those other forcing agents. The goal is to simulate the changes in the hydrological cycle with a specific focus on precipitation and surface water in orographically complex regions such as the western United States and the headwaters of the Amazon. For the cyrosphere, the objective is to examine the near-term risk of initiating the dynamic instability and onset of the collapse of the Antarctic Ice Sheet due to rapid melting by warming waters adjacent to the ice sheet grounding lines. The experiment would be the first fully coupled global simulation to include dynamic ice shelf-ocean interactions for addressing the potential instability associated with grounding line dynamics in marine ice sheets around Antarctica.