The French contribution to the Global Climate Observing System

France is participating fully in the Global Climate Observing System (GCOS). It incorporates the following four components: meteorological and atmospheric, oceanic, terrestrial, spatial, which will be briefly presented, especially in relation with the monitoring of the climate. The presentation will give an overview of the general principles governing the GCOS system and particularly the concepts used to maintain efficiently this climate observing system for a long period of time ("from research networks to operational networks"). The presentation will cover all the four components of the GCOS system. The whole report has been published in the Fifth National Communication from France to the UNFCCC (United Nations Framework Convention on Climate Change). The presentation will give an overview of the different networks of these four domains devoted to the monitoring of climate and maintained by France and highlighting the strengths and weaknesses of this climate observing system.