LARGE-SCALE EXPERIMENTAL AND MODELING STUDIES OF HYDROLOGICAL PROCESSES

The terrestrial hydrological cycle is a critical component of the Earth system, playing a key role in climate processes, biogeochemical cycles and their interactions. Better knowledge about the land/atmosphere exchanges of water is also needed to maintain human development, by improving water management practices and providing a better understanding of the local, regional and global consequences of human impacts on freshwater resources. Research into global hydrology is fostered under several international projects and programs. This paper briefly overviews past activity and progress in the field of large-scale observations and their associated modelling. It then previews upcoming activities, discerning a change of emphasis: increasing effort is now being given to broadening objectives, with more attention directed at larger-scale observations and truly interdisciplinary studies. These involve observations which are geographically widely-distributed, to sample a range of natural and man-made eco-climatological gradients.