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Benchmarking Pan-Arctic CMIP6 Model Streamflow to Observations: Understanding Utility across Different Spatial and Temporal Scales

Presentation Date
Thursday, December 15, 2022 at 3:10pm - Thursday, December 15, 2022 at 3:20pm
McCormick Place - E352



Earth System Models (ESMs) included in the Coupled-Model-Intercomparison Project (CMIP) are considered sophisticated in their ability to project the impacts of future climates on important hydroclimatic variables and Earth system processes. However, little is known about their performance against observations across standard hydrological metrics, which hampers our ability to understand their actual utility for direct use and applicability to answer science questions around a changing climate, particularly for high-latitude environments. We assess the performance of simulated Arctic runoff that has been routed to river channels using a physically based river routing model, Model for Scale Adaptive River Transport (MOSART), from ten CMIP6 models for metrics that have relevance for specific and important science questions. Metrics include low flow, high flow, flow timing, flow distribution, absolute error, flow variability, as well as trends and model bias, which are evaluated over multiple timescales (e.g. daily, monthly, and annual) across the Pan Arctic. Data are compared to observations from medium-to-large river basins (>10,000 km2, n = 997 gauges), as the coarse resolution of ESMs prohibits comparison for smaller river basins. Our results indicate that while one-to-one comparisons between ESMs and observations usually result in poor performance, the ESMs demonstrate some skill in prediction at coarser timesteps or when techniques such as statistical averaging and best-fit ESM selection were used. This work is anticipated to be highly useful for understanding the most appropriate applications for ESM when attempting to understand how Arctic hydrology will change under a future climate.

Funding Program Area(s)