GEO Tasks and satellite gravity missions

Douglas Cripe
GEO Secretariat, Geneva, Switzerland

The Global Earth Observation System of Systems (GEOSS) is a coordinating and integrating network of Earth observing and information systems, contributed on a voluntary basis by Members and Participating Organizations of the intergovernmental Group on Earth Observations (GEO). The purpose of GEOSS is to achieve comprehensive, coordinated and sustained observations of the Earth system, in order to improve monitoring of the state of the Earth, increase understanding of Earth processes, and enhance prediction of the behaviour of the Earth system. GEOSS will meet the need for timely, quality long-term global information as a basis for sound decision making, and will enhance delivery of benefits to society in multiple areas including, among others, improving water-resource management through better understanding of the water cycle.

Water-related issues addressed by GEOSS will include: precipitation; soil moisture; streamflow; lake and reservoir levels; snow cover; glaciers and ice; evaporation and transpiration; groundwater; and water quality and water use. GEOSS implementation aims to improve integrated water-resource management by bringing together observations, prediction, and decision-support systems and by creating better linkages to climate and other data. With respect to GRACE, GEO can facilitate the linking in-situ water-level observations with remote sensing information such as radar altimetry data and space-borne gravity data to produce products suitable for hind-casting, calibration of hydrometeorological models, water balance estimates, and early warning purposes (i.e. the onset of hydrological drought).