Statistical Downscaling via High-Dimensional Distribution Matching with Generative Models
High-resolution climate information is critically lacking for kilometer-scale regional climate risk assessment; existing statistical downscaling methods suffer from poor scalability, narrow hazard adaptability, and inability to model physical dependencies among multivariate climate fields. Method: We propose GenBCSR, a two-stage generative framework that—uniquely—decouples statistical downscaling into bias correction and statistical super-resolution, formulated as two high-dimensional distribution alignment tasks, eliminating reliance on pixel-wise paired labels. Leveraging diffusion- or flow-based probabilistic distribution matching, it enables efficient, physics-consistent upscaling under unsupervised or weakly supervised settings. Results: GenBCSR reduces prediction error by 4–5× for compound extreme-event indices (e.g., 99th-percentile metrics) versus conventional methods, achieving superior accuracy, computational efficiency, and physical interpretability.