The IGCP 565 Project

Objectives

The Global Geodetic Observing System (GGOS) of the International Association of Geodesy (IAG) observes the Earth's time-variable gravity field, shape, and rotation (Drewes, 2006). With these observations, GGOS not only provides the observational basis for the maintenance of a global terrestrial reference frame as the foundation for all Earth observations, it also provides observations directly related to global change processes. At time scales from weeks to decades, hydrological loading of the Earth's surface dominates non-secular variation in each of the three fundamental areas of geodesy. Thus, geodesy inherently provides valuable constraints on the global water cycle at multiple spatial and temporal scales. In particular, the space geodetic sensors capture the signals of variation in the entire fluid envelope of the solid Earth, including the terrestrial water storage. Space geodetic observations of surface mass variability are inherently strong at regional to global scales. Therefore, GGOS offers a monitoring system that can complement traditional in-situ measurements of terrestrial water storage through geodetic remote sensing.

The IGCP 565 Project has the main objectives to:

• explore and develop the components of GGOS that are most relevant for monitoring the water cycle;
• make the observations available for assimilation in predictive models of the global water cycle;
• interpret the observations in terms of changes in terrestrial water storage;
• develop products and algorithms that will allow regional water management to fully utilize the potential of the geodetic techniques for monitoring the regional terrestrial hydrosphere;
• assess the extent and way in which the projected climate change might affect the hydrological cycle and the availability of water to society in the various regions.