Evaluating a Novel Approach to Simulating Climate Change

What is it about?

Here, we present a novel set of atmospheric simulations designed to address changes in high-impact weather events. The model covers the globe, but has higher resolution in the Northern Hemisphere. We simulate ten years sampling a range of tropical climate conditions, as represented by observed ocean surface temperatures, and we carry out simulations for current and projected late 21st-century climate conditions. The future runs include increased heat-trapping gases, higher ocean temperatures, and reduced polar sea ice as projected by conventional global climate models. Our model reasonably replicates present-day climate features, such as large-scale precipitation patterns, mid-latitude cyclone activity, the jet stream, and tropical cyclone characteristics. It reproduces features of climate change that are expected from global climate models, but it also captures smaller scale, high-impact weather events.

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Why is it important?

We expect that high-impact weather events will change in a warmer climate. Computational constraints limit global climate models to resolutions that are too coarse to fully capture many societally significant weather events, such as tropical cyclones and flooding rains in middle-latitude low-pressure systems. While these global models often provide reliable projections of changes in mean temperatures and global circulation patterns, they cannot tell us how intense, high-impact events may be altered in response to climate change. Our simulations are run at sufficiently fine resolutions to capture these smaller scale features. Therefore, we anticipate that these simulations will have great value in understanding changes in high-impact weather events.