Bridging the Gap: Integrating Urban Land Surface and Hydrology Models for Enhanced Urban Hydrometeorology

Given the increasing significance of urban hydro-thermal research, including the evaluation of green-blue spaces and hydro-meteorological risk assessment, it is crucial to explore advanced simulation tools for urban hydro-meteorology. Typically, urban thermal environments and water resource management are treated as separate fields, studied independently using urban land surface models (ULSMs) and hydrology models (UHMs). This critical review addresses three main questions: 1) What are the similarities and differences between various urban land surface and hydrology models? 2) What gaps exist between these models? 3) What are the current capabilities of simulation tools for urban hydrometeorology?

Canyon concept ULSMs are the most widely used simulation tools and have seen rapid development. In contrast, distributed UHMs, which show greater potential for the hydrometeorology interface, are less commonly adopted due to the requirement for high-resolution input data. Our comparison of the complexity of physical processes and schematic methods reveals that ULSMs often inadequately represent water surfaces, while UHMs lack explicit surface energy balance solutions and detailed building representations. ULSMs focus on vertical water transfer within unsaturated soil layers, whereas UHMs address saturated soil layers and lateral runoff. Most ULSMs lack a comprehensive hydraulic system, often assuming unlimited pipe capacities for surface runoff.

The review highlights the importance of implementing and coupling processes across the atmosphere, land surface, and subsurface to bridge the gap in simulating urban hydrometeorology. Enhanced interdisciplinary communication between urban climate and urban water management is encouraged.