Setting the Requirements for Climate Observation and Monitoring
Simmons, Adrian
European Centre for Medium-Range Weather Forecasts, UNITED KINGDOM

Our overall global observing system for climate comprises a diverse set of in situ and remotely-sensed measurements of the state of the atmosphere, land and ocean made under various auspices, often for purposes other than or additional to climate, and organised to a greater or lesser degree into contributing networks and subsystems.
The programme for the Global Climate Observing System (GCOS) was set up by its sponsors (WMO, IOC/UNESCO, UNEP and ICSU) to view climate observation as a whole, so as to help ensure that observational needs are met for monitoring to detect change and determine impacts, for services that support national economic development and for research into improved understanding, modelling and prediction. GCOS covers not only the making of observations, but also how the resulting data are managed, including recovery of older data, and formed into records and derived products. It works in liaison with the partner programmes of its sponsors and others, including the space agencies and their coordinating bodies. GCOS has set out requirements for climate observations and data products organised around a set of Essential Climate Variables, promoted monitoring principles and developed guidelines for dataset production and for national reporting on systematic observation under the United Nations Framework Convention on Climate Change. Its work has provided the basis for responses such as ESA's Climate Change Initiative.
The talk will outline programmatic aspects and illustrate the evolving status of climate observation. It will also summarise the steps to be undertaken by GCOS in its forthcoming review of progress and adequacy, and consequent revision of requirements, which will take into account conclusions of the Fifth Assessment by the Intergovernmental Panel on Climate Change and initiatives such as the emerging Global Framework for Climate Services.