Improved Urban Finescale Forecasting During a Heat Wave by Using High-Resolution Urban Canopy Parameters

Abstract

For urban weather finescale forecasting, obtaining accurate and up-to-date urban canopy parameters (UCPs) is necessary and still a challenge. In this study, a high-resolution dataset of UCPs was developed by using vector-format building information and then applied in the WRF/urban system with the single-layer urban canopy model (SLUCM)/building effect parameterization (BEP) model to improve the urban finescale forecasting of a typical heat wave event during summer 2016 in Hangzhou. A series of sensitivity experiments were conducted, and the results showed that the high-resolution UCP data improved the model skill in simulating the spatial distributions and diurnal variations of 2-m temperature, 2-m relative humidity, and 10-m wind speed in the urban areas of Hangzhou, especially for the BEP model. Better results were produced when refining the computation domain due to more realistic urban morphological characteristics were adopted. The sensitive experiments suggest that the high-resolution UCPs played a significant role in representing the UHI effect though changing the surface thermodynamic parameters (e.g., roughness length), hereafter increasing the sensible heat and surface heat flux, and finally resulting a notable urban heat island (UHI) effect.

Hyper‐Local Temperature Prediction Using Detailed Urban Climate Informatics

“…However, due to the limitations of computational resources and model stability, it is challenging to incorporate exhaustive geospatial information into physical‐based models. The recent implementations of urban canopy parameterization and LCZ in uWRF have demonstrated the growing demand for high‐resolution urban simulations (F. Chen et al., 2022). In our study, we find that the averaging range affects model performance in a non‐monotonic manner, suggesting that there is an optimum scale for certain urban features when simulating built environments (Section 3.1).…”

“…It is also extremely difficult to find the finest cell size that can reflect the hyper‐local urban characteristics without breaking the physical schemes in the model simulation. Even with the most advanced urban parameterization schemes (F. Chen et al., 2022; Shen et al., 2019), modeling microclimate at meter scale and pedestrian level is beyond the resolving power of the current generation of uWRF.…”

Novel Geometric Parameters for Assessing Flow Over Realistic Versus Idealized Urban Arrays

“…For realistic urban layouts, domains are selected with a similar size to the state‐of‐the‐art grid resolution of mesoscale models (Δ x = Δ y ∼ 300 m, e.g., F. Chen et al., 2022; Leroyer et al., 2014), that is, each case could be deemed as one grid cell in a high‐resolution mesoscale model. This arrangement further ensures evaluations among different urban surfaces precisely address the inter‐grid variability of urban flow in mesoscale modeling.…”

Impacts of Urbanization and Its Parameters on Thermal and Dynamic Fields in Hangzhou: A Sensitivity Study Using the Weather Research and Forecasting Urban Model

“…In the last few years, our understanding of the impact of urbanization has greatly advanced thanks to Numerical Weather Prediction (NWP) models [14][15][16]. To consider the effects of urban areas within NWP models, different parameterizations have been developed, for example, the single-layer urban canopy model (SLUCM) [17,18] and building effect parameterization (BEP) [19], to take into account urban-scale processes within mesoscale models, and they are currently implemented in the Weather Research and Forecasting (WRF) model [20].…”