Evaluating parameterization of anthropogenic heat release in urban land surface scheme from field measurements and energy consumption inventory over Toulouse during CAPITOUL

The CAPITOUL field program is a French initiative to study the impact on the atmosphere of the urbanized areas of Toulouse agglomeration (south west of France) for a one-year period (Feb. 2004-Feb. 2005) . Toulouse is a typical old European city with a dense old core characterized by narrow streets, brick walls and tile roofs. The instrumental device consisted of sites measuring flux densities (3), wind profilers (2), a ceilometer, an urban network measuring air temperature and relative humidity at 20 sites inside the agglomeration, and rural weather stations around the agglomeration (3). The anthropogenic heat flux (QF) is a supplementary source of energy in comparison to the classical surface energy balance drawn on a rural area. In summer, this term is often neglected. In winter, it must be taken into account, especially in the dense old core of the city where density of buildings and traffic are the highest. In dense European urban areas, the major source of QF is the domestic heating of buildings. In urban land surface schemes this term can be parameterized, for example by assigning a steady internal temperature inside the buildings. In this paper, we evaluate such a parameterization against two independent methodologies of estimation of QF. The first one is based on the measurements at the central site. QF is computed as the mean residual over whole day periods. With this methodology we don't have access to diurnal nor spatial variability of this term. The second one is a direct evaluation of anthropogenic energy release from inventories of traffic and electricity and fossil fuel consumption inside the housings. This methodology gives access to diurnal as well as (for specific types of energy), to spatial variability.