Water effects on urban heat islands in summer using WRF-UCM with gridded urban canopy parameters — A case study of Wuhan. (November 2022)

• Record Type: Journal Article
• Authors: Zhu, Dun; Zhou, Xuefan; Cheng, Wei
• Is Part Of: Building and environment. Volume 225(2022)
• Publication Date: 2022-11
• Subjects: Urban heat islands -- Water body -- Ventilation channel -- WRF-UCM -- Urban canopy parameters (UCPs); Buildings -- Environmental engineering -- Periodicals; Building -- Research -- Periodicals; Constructions -- Technique de l'environnement -- Périodiques; Electronic journals; 696
• DOI: 10.1016/j.buildenv.2022.109528
• Languages: English
• ISSNs: 0360-1323

Abstract

Abstract: Urbanization has rapidly occurred in China along with a significant reduction in ecological resources, greatly exacerbating urban heat island effect. In cities with abundant inland lake resources, it is valuable to study the use of climate regulation effects of water bodies to improve the urban climate environment. In this study, we built a single-layer urban canopy model with higher accuracy by importing gridded urban canopy parameters and studied the impact of water bodies distributed in different areas of Wuhan on the urban thermal environment using a weather research and forecasting model (WRF). Water bodies located in the upwind suburbs had the greatest cooling impact on the microclimate of downtown areas during the day. Furthermore, they promote the evacuation of heat inside the urban canopy to the upper air by enhancing the lake breeze circulation. Late morning temperatures drop above the ground when the breeze circulation fully develops, while the temperature rise in the upper air increases. However, the cooling effect of these water bodies on the downtown area was affected by construction intensity in the suburbs. When the building density increased from 20% to 40%, the cooling effect did not change significantly. However, a further increase from 40% to 60% increased the proportion of intense heat island areas downtown, and the cooling effect of water bodies was also severely weakened. Moreover, with an increase in building density in the suburbs, the intense heat island areas north of the city gradually expanded to the city center. Highlights: Alleviating urban heat island by the ecological effect of water bodies. A more accurate urban canopy model for Wuhan City was built using the UCPs. Upwind suburban water bodies enhance horizontal and vertical heat evacuation. The development of the lake-breeze intensity and cooling effect was not synchronous. The cooling effect of water bodies is affected by construction intensity.