Comparative estimates of anthropogenic heat emission in relation to surface energy balance of a subtropical urban neighborhood

Long-term eddy covariance measurements have been conducted in a subtropical urban area, an older neighborhood north of downtown Houston. The measured net radiation (Q*), sensible heat flux (H) and latent heat flux (LE) showed typical seasonal diurnal variations in urban areas: highest in summer; lowest in winter. From an analysis of a subset of the first two years of measurements, we find that approximately 42% of Q* is converted into H, and 22% into LE during daytime. The local anthropogenic heat emissions were estimated conventionally using the long-term residual method and the heat emission inventory approach. We also developed a footprint-weighted inventory approach, which combines the inventory approach with flux footprint calculations. The results show a range of annual anthropogenic heat fluxes from 20 W m−2 to 30 W m−2 within the study domain. Possibly as a result of local radiation versus heat flux footprint mismatches, the mean value of surface heat storage (ΔQs) was relatively large, approximately 43% and 34% of Q* in summer and winter, respectively, during daytime.