Ultraparameterization: A New Strategy for Including Explicit Low Cloud Physics in Global Climate Models at the GPU-Accelerated Petascale

Low cloud feedbacks are critical to climate model projections but explicitly representing low cloud physics in global climate models (GCMs) can seem computationally prohibitive due to the extreme eddy resolution required (250 m horizontal and 20 m vertical). We present a vision called “ultraparameterization” that leverages current leadership class computer hardware and new algorithmithic techniques to make the problem tractable on GPU-accelerated petascale computers, based on a heterogeneously multi-scale approach. Pilot test results from the new “ultraparameterized” Community Earth System Model (UPCESM) under development are shown and technical challenges of doing climate simulation at this extreme scale are discussed.