Predicting the unpredictable: Advances in Tracer-aided hydrologic modeling

As global climate change alters hydroclimatic responses beyond the range of predictability based on historic hydrometeorological records, water resource practitioners are increasingly reliant on new methods of modelling continental and global hydrology. Though local scale heterogeneity and connectivity between hydrologic storages and fluxes tends to be averaged out across large domains, it is precisely these process scale changes that remain crucial as early indicators of climate change. A lack of data at continental scales, and particularly in high latitude regions, can therefore challenge accurate model calibration and evaluation. Efficient and accessible hydrologic prediction tools capable of diagnosing and interpreting continental scale changes in water balance components and overall water supply, ecosystem changes, and uncertainty methods for operational decision-making are needed.

This presentation focuses on the recent advances in large-domain tracer-aided stable isotope modelling and the contributions isotope tracers make on improving hydrologic process representation across large-domains. The influence of process-based model outcomes will be highlighted using examples from cold regions domains, including the propagation of small historical differences into significantly different upper quantile flow predictions. Despite significant advances in tracer-aided modelling, the path forward must include building and supporting global operational monitoring networks, providing standard guidance for integration of tracer-aided approaches, and a focus on building model agnostic workflows and tools that efficiently leverage tracer-aided approaches.