Interactions between terrestrial ecosystem water and carbon cycles and their simulation methods; a review

This paper reviewed the researches on the interactions between water and carbon cycles in terrestrial ecosystems, and the algorithms developed to simulate these cycles and their interactions. Future research efforts to be taken were also suggested. Carbon and water cycles are the coupled ecological processes in terrestrial ecosystems. They themselves and their interactions are affected by climate, atmospheric composition, and human activities, and impose significant feedbacks on climate system, being the research focuses in global change study. Many observational and modeling studies have been conducted to study the interactions of the two cycles at various spatial and temporal scales as well as their responses to the changes in environmental factors and land cover. Soil water markedly affects the main components of the carbon cycle (photosynthesis and respiration), but the affecting strength varies with the types of ecosystems. To accurately simulate soil water dynamics and its roles in the carbon cycle is the basis of reliable simulation of terrestrial carbon budget. Efforts should be taken to implement coupled modeling of carbon and water cycles in ecological and hydrological models. Most of current models ignore the effects of topography on the horizontal redistribution of soil water, and utilize empirical methods to simulate the effects of soil water on heterotrophic respiration, which limit the reliability of carbon budget estimation and needs to be resolved.