Evaluating Arctic clouds across scales: A comparison of clouds in large-scale and multi-scale models with ARM observations over the North Slope of Alaska

Description

The radiative effects of clouds have important implications for climate change in the Arctic, but current large-scale models struggle to simulate the amount and phase of these clouds. Mixed-phase clouds are prevalent in high latitudes but are particularly challenging for large-scale models to simulate. This stems from an incomplete representation of liquid and ice condensate and the partitioning between the two in cloud physics parameterizations, and points to a need for improved understanding of processes important to cold clouds. The wealth of data being collected on the North Slope of Alaska at Atmospheric Radiation Measurement (ARM) research facilities at Barrow and Oliktok offers an unprecedented opportunity to further our understanding of these processes and the sources of model errors. We compare simulations from a traditional large-scale model (CAM5) and from a multi-scale model that implements a 2-dimensional cloud-resolving model into each gridbox to replace the cloud and convection parameterizations with explicit simulation of clouds and convection (SP-CAM 2.0) with observations from the ARM sites on the North Slope of Alaska. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-AC04-94AL85000. SAND NO. SAND2017-0202 A