Evaluation of the Surface Urban Energy and Water Balance Scheme (SUEWS) at a Dense Urban Site in Shanghai: Sensitivity to Anthropogenic Heat and Irrigation

The Surface Urban Energy and Water Balance Scheme (SUEWS) is used to investigate the impact of anthropogenic heat flux Q(F) and irrigation on surface energy balance partitioning in a central business district of Shanghai. Diurnal profiles of Q(F) are carefully derived based on city-specific hourly electricity consumption data, hourly traffic data, and dynamic population density. The Q(F) is estimated to be largest in summer (mean daily peak 236 W m(-2)). When Q(F) is omitted, the SUEWS sensible heat flux Q(H) reproduces the observed diurnal pattern generally well, but the magnitude is underestimated compared to observations for all seasons. When Q(F) is included, the Q(H) estimates are improved in spring, summer, and autumn but are poorer in winter, indicating winter Q(F) is overestimated. Inclusion of Q(F) has little influence on the simulated latent heat flux Q(E) but improves the storage heat flux estimates except in winter. Irrigation, both amount and frequency, has a large impact on Q(E). When irrigation is not considered, the simulated Q(E) is underestimated for all seasons. The mean summer daytime Q(E) is largely overestimated compared to observations under continuous irrigation conditions. Model results are improved when irrigation occurs with a 3-day frequency, especially in summer. Results are consistent with observed monthly outdoor water use. This study highlights the importance of appropriately including Q(F) and irrigation in urban land surface modelsterms not generally considered in many previous studies.