UrbanSurface-Agent: Physics-Gated Scientific Reasoning for Urban Surface Parameterization

Urban land-surface numerical models are important tools for simulating urban energy exchanges and local climate. However, improvements in model performance do not necessarily imply scientifically valid parameterization, because compensating errors among coupled processes can make inappropriate parameter changes appear beneficial. To address this issue, we introduce UrbanSurface-Agent, a physics-gated scientific agent that formalizes parameter discovery as an experience-guided proposal–verification process. Model–observation discrepancies are used to formulate mechanism-guided parameter interventions with expected process responses, which are evaluated by SUEWS and independently adjudicated by a Physics Judge using semantic, process-wise, and temporal criteria. Experimental outcomes, including successful, failed, and boundary-case interventions, are retained in scientific memory to guide subsequent proposals. We evaluate UrbanSurface-Agent on 20 Urban-PLUMBER flux-tower sites under a sealed temporal protocol. Across 1,410 adaptation candidates, 350 improve the aggregate objective but fail process consistency and 89 further fail temporal consistency, demonstrating that numerical improvement alone is insufficient for reliable parameter discovery. The framework freezes interventions at 16 sites, with 14 satisfying practical success criteria on the sealed future period. These results demonstrate that reliable scientific-agent parameter discovery requires more than numerical optimization: proposed corrections must be tested against the physical processes they are intended to represent, and transferable scientific knowledge is better represented by context-dependent parameter–process evidence than by universal numerical corrections.