Modeling of CO2 Fluxes: Study of the Interactions of Urban Climate with CO2

The quantity of CO2 present in the atmosphere at any given moment is the result of complex exchanges and balances between the atmosphere and the Earth's surface. The Earth's surface is composed not only of oceans, vegetation and natural soils, but also cities. There are therefore strong interactions between climate and CO2 at the scale of the city: the city's carbon balance depends on the local climate, and the transport of CO2 through the atmosphere is induced by the atmospheric circulation induced by the city. The modelling of CO2 exchanges between urban surfaces and the atmosphere in the urban micro-climate model TEB. This verified that the physical processes linking urban CO2 emissions/captures and urban climate were well identified and understood. The model was evaluated on two case studies; each one allows a more specific assessment of given the contributors to the city/atmosphere CO2 exchanges. The model, thus validated, was used to carry out simulations of CO2 emissions from buildings on the scale of the entire urban agglomeration of Casablanca. These simulations once again highlighted the importance of a good knowledge of the energy behaviour of the inhabitants: in our case, the study was carried out for three days of the week in winter; the reduction of 0.5 degrees C of the set temperature of the heating system at night reduces CO2 emissions by 20%. During these simulations, the transport of CO2 emitted by the city through the atmosphere was also monitored. It was thus shown that, despite a calm wind situation, the CO2 plume created by the city dissipates rapidly, which limits the increase in CO2 concentration over the city.