FOCAL AREA(s)• Primary: 3 ("Insights gleaned from complex data … physicsor knowledge-guided AI") • Secondary: 2 ("Predictive modeling through the use of AI … hierarchy of models") This white paper focuses on methods that blend AI and science (e.g., physics, biogeochemistry) by (a) guiding AI cost functions, trajectories and representations with science knowledge and/or with context-specific data-driven insights in a Bayesian-inspired framework; (b) framing AI models in the context of physics-informed dynamic, causal networks; (c) merging AI-enhanced science models with science-guided explainable AI; (d) focusing on statistics/processes related to extremes and translations to risks in a changing world; & (e) identifying model parameterizations or components that must be improved to minimize risks and add maximum value to stakeholders.
SCIENCE CHALLENGEA grand challenge [1-10] in hydrologic science is to understand why signals of climate change and variability, which are often visible in precipitation extremes at aggregate scales, are not consistently observed in the case of extreme flooding. However, a solution to this challenge may prove elusive unless the water cycle is viewed in an integrative manner. Thus, for riverine flooding, while Hortonian (infiltration excess) runoff may have stronger correlation with precipitation extremes and hence perhaps to warming trends or climate oscillators, Dunne (saturation excess) runoff may have a more complex relationships with time series of precipitation and with evaporation and transpiration, but rain-on-snow and snowmelt events may depend on land-surface and atmospheric temperatures. Atmospheric rivers [11] and tropical cyclones [12] lead to precipitation or flooding and are impacted by climate. Flooding assessments need to consider long-term baselines [13], evolving risk factors [14], coupled natural-human systems [15][16], and novel adaptation such as nature-inspired design [17][18].
RATIONALEThe urgency of stakeholder needs pertaining to precipitation and flooding extremes requires transformative advances in long-standing challenges within earth systems sciences. Challenges for which emerging AI solutions have started to make a difference include (a) cloud physics and subgrid processes [19][20][21][22][23][24]; (b) spatiotemporal patterns and dependencies [25-29; 44]; (c) climate oscillations and teleconnections with regional hydrology [30][31][32][33][34][35]; (d) pattern search across multiple ensembles [35][36]; and (e) statistical downscaling [37-40; 45]. The AI solutions cited have ranged from machine learning (including Deep Learning), network-based approaches, and