Important land surface characteristics affect the way in which water is transferred to the atmosphere, processed in the atmosphere, and eventually returned to the surface. In turn, the amount of water in the atmosphere and returning to Earth affects many of the key properties of the land surface. It is hypothesized that feedbacks between the terrestrial biosphere and the atmosphere by way of biogenic aerosol pathways exist, and that these feedbacks can be important in both direct and indirect radiative processes. By investigating this coupled cycle, a better understanding of the Earth system, including climate change, regional and global atmospheric chemistry, haze and visibility, weather, and changes in land cover is obtained.