Estimation of anthropogenic heat release in Mexico City

Abstract

The urban heat island (UHI) is a phenomenon that appears in cities due to the alteration of the energy balance caused by the drastic land use change. A factor that can contribute to its development is the energy generated by the city inhabitants, or the anthropogenic heat flux (QF). Therefore, the determination of this component can improve the predictability of UHI development and variability. The objective of this work was to estimate the main sources of anthropogenic heat flux, based on a vehicle classification (taxis, cars, minibuses and buses), surveys of electricity consumption and population density in Mexico City. The anthropogenic heat determination is based on a simple distribution of heat generated by vehicles, buildings and people. Vehicle classification was made through video analysis and the vehicle flow was also accounted for with sensors at the road level, within a radius of 1 km. The consumer surveys were applied to businesses and homes, and with the support of basic geostatistical areas the population density was determined. The analysis showed that the highest heat emission occurs from 15:00 to 21:00 h. This heat flux in average was not significant when compared to net radiation. However, anthropogenic heat flux generation in dense areas of Mexico City, can exceed 75 W·m−2 for certain times of the day, while the inventory carried out QF averaged 24.7 W·m−2 at San Agustin, in the historical center. With the obtained results, also a standard car was idealized, and the electricity consumption profiles of some sectors were generated, which will allow obtaining the heat flux more easily and quickly. According to the results, it is advisable to integrate the anthropogenic heat flux component into the energy balance for future studies of the UHI.