Sensitivity of predicted pollutant levels to anthropogenic heat emissions in Beijing

Abstract

A new parameterization method for anthropogenic heat (AH) parameterization (called NewLUCY) is developed in the WRF-Chem model, which estimates hourly heat fluxes with a single-peak diurnal variation pattern and utilizes updated urban built-up land use data. The impacts of accounting for anthropogenic heat (AH) fluxes on the meteorology and air quality of the Greater Beijing area are studied using this upgraded WRF-Chem model system. Including AH is shown to increase the surface temperature by 0.8°C in daytime and 1.2 °C at nighttime. The Planetary Boundary Layer (PBL) heights are also increased, with a maximum incrementation exceeding 320 m during daytime and 160 m at night. Spatial and vertical distributions of the simulated pollutants are also impacted by the AH. Surface ozone concentrations increase in the urban areas (4ppb for daytime and 18 ppb for nighttime) when AH is included in the analyses. Moreover, the impacts of AH are not limited to the urban centers, but extend regionally. For example, the simulated PM2.5 concentrations increase in the rural areas as well, due to a decrease in rural precipitation rates when AH is included. In general, incorporation of AH increases the accuracy of the predictions comparing to the observations. At the Peking University site (PKU), the mean error (ME) of the 2-m temperature prediction is reduced from 1.55 °C to 0.61 °C. The predictions of the high ozone episodes are also improved.