PNNL

Abstract

Accurate representation of urban properties and processes at higher resolutions in global modeling systems is essential for advancing urban climate science and informing effective resilience strategies. However, the prescription of coarse global-scale urban properties in most state-of-the-art Earth system models is limiting their potential for capturing these climate signals as they advance toward kilometer-scale simulation capabilities. To bridge this gap in inadequate urban property representation and to advance urban-resolving Earth system modeling, this work integrates the newly-developed global 1 km-resolution facet-level urban surface property dataset, U-Surf, into the Community Earth System Model (CESM). These CESM simulations are validated against satellite measurements, ground-based urban weather stations, flux tower observations, and reanalysis data. Results demonstrate that the enhanced urban properties allow improved simulations of urban meteorology and surface energy fluxes compared to the default coarse-resolution categorical urban canopy parameters. Spatial scaling analysis reveals climate-dependent information loss during resolution aggregation, as well as substantial scale-dependent variations in urban surface energy flux representation. These findings have critical implications for coupled Earth system modeling when including the effect of land-atmosphere interaction. This work establishes a foundation for future urban-resolving kilometer-scale ESM development, which will enable systematic intra- and inter-city comparisons that inform urban adaptation strategies across diverse global urban environments.