The continuous increase of world’s cities sprawl, in a context of global change, makes it urgent to promote the sustainability of these areas. But an integrated and systemic approach is required to face with simultaneous environmental, economic and social challenges. The concept of critical zone offers an adapted framework to develop integrated approach, but it needs to be adapted to the specificities of the zones where humans live and work. The critical zone is defined initially as the thin and heterogeneous and near surface environment in which occur interactions involving rock, soil, water, air, and terrestrial ecosystems. In urban areas, the critical zone is strongly transformed by the infrastructure, facilities and buildings, and impacted by human activities and usages which heavily affect the fluxes and balances of water, energy, and chemicals including pollutants….In this session, we will address the question of the biophysical processes specificities of the urban critical zone that interact with anthropic processes controlled by human activities and stakeholders. Most of the urban geophysical processes are studied are very local and small levels, it is necessary to produce interdisciplinary knowledge are more global scales.

We invite contributions of experience on urban critical zones and especially those including observations, measurements of fluxes, description of biogeochemical, physical and human resilience processes and development of models to respond to these crosscutting issues. Proposals coming from diverse urban contexts (size, growth patterns, geographical, social) at different spatial and temporal scales will be appreciated. We aim at forstering interdisciplinary dialogue to make the Urban Critical Zone a unifying concept.