Coupled models for the hydrological cycle : integrating atmosphere biosphere and pedosphere ; with 20 tables Modeling groundwater is a tool familiar to all working in this field. Coupling different compartments has emerged as a challenge to the modeling community. This book contributes to these discussions and gives a state of the art summary of the different ways of coupling. Firstthe cycles which have to be taken into account are beeing presented then the scale issue and multiple equilibria are discussed. Inter and intra compartmental coupling is dealt with followed by a debate on non linearities and questions of parameterization. All these issues are dealt with on a theoretical level before applied to the hydrological cycle itself. Case studies exemplify how coupling can help to solve special questions from the local to the global cycle. TOC:1.Cycles Feedbacks and Main Issues. Global cycles: Overview and Introduction. The Nature of Land Biosphere Atmospheric Feedbacks in the Hydrological Cycle. Scale issues. Multiple Equilibria. 2.Systems Approach: The Nature of Coupled Models. Introduction. Fluxes Compartments and Ordering of Feedbacks. Non linearities. Parameterization of Complex Hydrological Systems. 3.Systematization of the Interactions between Hydrological and Related Cycles. Introduction. Coupled Processes and Interaction Matrix. Coupling Aspects of Heat and Mass Transfer. Feedbacks at the Hydro metreorological Interface. 4.Case Studies. Framework of the Case Studies. 5.Summary and Outlook. 6. Glossary