Local climate effects of urban wind corridors in Beijing

Abstract

Based on a summer observational experiment and the meteorological data from 2009 to 2018, this paper investigated the local climate effects of representative 1 Level One and 2 Level Two wind corridors (LOC and LTCs, respectively) in the central urban area (CUA) of Beijing by introducing the wind speed ratio (WsR) and urban heat island (UHI) intensity indices. In addition, the impacts on the ventilation of wind corridors from the 8 spatial landscape parameters were analyzed. The results indicated that LOC and LTCs have significant ventilation benefit and certain UHI mitigation benefit varying with season, day and night and weather，which were able to accelerate winds when wind speeds exceed 0.57 m/s and 0.75 m/s, respectively. The most important influencing parameters on the ventilation capability were frontal area index and roughness length. The multiyear average WsRs of the LOC and LTCs were 57% and 31% higher than that of the CUA, respectively. The UHI reduction did not occur along the whole corridor or throughout the whole day. The maximum seasonal mean UHI reduction of the LOC during daytime and nighttime were 0.89 °C and 0.75 °C, respectively. The LTCs mainly reduced UHI during daytime with the maximum reduction of 0.30 °C.