Interactions and feedbacks between climate and dryland vegetations

Abstract

Interactions and feedbacks between terrestrial ecosystem processes and climate mainly take effect through biophysical and biogeo-chemical processes and affect atmospheric circulation, regional water cycles and the carbon budget. In biophysical processes, the atmosphere and the land-surface exchange radiation, heat, and momentum fluxes, as well as water vapor. Biophysical feedbacks affect atmospheric conditions by modifying evaporation, runoff, energy partitioning between latent heat and sensible heat fluxes, and upward radiation fluxes. Biogeochemical processes affect climate by altering atmospheric composition and the atmospheric radiation balance, especially by modifying exchange of trace gases, such as carbon dioxide and aerosols, between terrestrial ecosystems and the atmosphere. Figure 1 is a schematic diagram showing the exchange processes between land and atmosphere. This chapter mainly focuses on biophysical feedback.