A multi-method and multi-scale approach for estimating city-wide anthropogenic heat fluxes

• Main Authors: CHOW, Winston T. L., SALAMANCA, Francisco, GERGESCU, Matei, MAHALOV, Alex, MILNE, Jeffrey, RUDDELL, Benjamin L.
• Format: text
• Language: English
• Published: Institutional Knowledge at Singapore Management University 2014
• Subjects: Anthropogenic heat; Waste heat; Urban climate; Environmental Sciences
• Online Access: https://ink.library.smu.edu.sg/soss_research/3052; https://ink.library.smu.edu.sg/context/soss_research/article/4309/viewcontent/1_s2.0_S1352231014007468_main__1_.pdf
• Institution: Singapore Management University

A multi-method approach estimating summer waste heat emissions from anthropogenic activities (QF)was applied for a major subtropical city (Phoenix, AZ). These included detailed, quality-controlled in-ventories of city-wide population density and traffic counts to estimate waste heat emissions frompopulation and vehicular sources respectively, and also included waste heat simulations derived fromurban electrical consumption generated by a coupled building energyeregional climate model (WRF-BEMBEP). These componentQFdata were subsequently summed and mapped through GeographicInformation Systems techniques to enable analysis over local (i.e. census-tract) and regional (i.e.metropolitan area) scales. Through this approach, local mean dailyQFestimates compared reasonablyversus (1.) observed daily surface energy balance residuals from an eddy covariance tower sited within aresidential area and (2.) estimates from inventory methods employed in a prior study, with improvedsensitivity to temperature and precipitation variations. Regional analysis indicates substantial variationsin both mean and maximum dailyQF, which varied with urban land use type. Average regional dailyQFwas ~13 W m2for the summer period. Temporal analyses also indicated notable differences using thisapproach with previous estimates ofQFin Phoenix over different land uses, with much larger peakfluxesaveraging ~50 W m2occurring in commercial or industrial areas during late summer afternoons. Thespatio-temporal analysis ofQFalso suggests that it may influence the form and intensity of the Phoenixurban heat island, specifically through additional early evening heat input, and by modifying the urbanboundary layer structure through increased turbulence.