Nancy Y Kiang

This opportunity is to conduct research on how the Earth's terrestrial biosphere interacts with the atmosphere, and how feedbacks between the two affect climate, the distribution and composition of ecosystems, and the carbon balance of an Earth-like planet. The coupling between the carbon and nitrogen cycles is a central theme, as the changing nitrogen status of an ecosystem can direct its trajectory through time. Our primary tool is development of process-based models to simulate ecosystem dynamics and surface fluxes of carbon, water vapor, and energy, coupled with land surface hydrology models and general circulation models (GCMs) of the atmosphere. This land-based ecosystem modeling is being coupled with the GISS GCM in coordination with other scientists working on ocean biogeochemistry and atmospheric tracers. Some questions we focus on with regard to terrestrial ecosystems include: prediction of albedo for mixed ecosystems, accounting for light stratification of plant dynamics; dynamic allocation of carbon and nitrogen in plants, especially in the construction of the photosynthetic apparatus and allocation to roots; impact of high CO2 concentrations on plant physiology and ecosystem carbon storage; interannual variation in vegetation phenology and ecosystem-atmosphere exchanges; mathematical modeling of plant community competition and soil biogeochemistry; vegetation change due to climate, disturbance, and competition for light, water, and nutrients; and sensitivity of soil carbon storage to soil depth and climate change.