Abstract ID: 578

Diurnal and Annual Cycles and Interannual Variabiliity in Photosynthesis, Respiration and Net Ecosystem Exchange (NEE) Among Participants in the LBA Model Intercomparison Study (LBA-MIP).

We evaluate the ecophysiological response, in the form of carbon flux, of participant models in the LBA-MIP to meteorological forcing. In heavily vegetated regions (such as Amazonia) the Bowen Ratio is tightly coupled to stomatal regulation of transpiration. Therefore, latent and sensible heat fluxes will be strongly dependent upon carbon flux. Modeled Net Ecosystem Exchange (NEE) of Carbon is the unique combination of photosynthetic and respiratory fluxes. Model carbon uptake is a function of photosynthetic potential diminished by stress factors, usually related to temperature, humidity and soil moisture. Efflux will be determined by Carbon storage reservoirs and factors that regulate respiration such as soil temperature and moisture. By comparing model component mechanism behavior we can classify models by their behavior and evaluate their performance. Modeled photosynthesis will resonate throughout the entire land-atmosphere interaction. Evaporation, runoff, temperature, and Bowen Ratio will all feel the influence of canopy ecophysiology. We investigate carbon flux on diurnal, seasonal and interannual timescales, and evaluate carbon flux influence on hydrological and energy cycles. Detailed intermodel comparison of carbon processes and related canopy mechanisms provides insight into our understanding of multiple aspects of ecophysiology across the Amazon Basin. We find that model results stratify across different parameterizations of physical processes.

Session:  Carbon - The LBA Model-Intercomparison Project.

Presentation Type:  Oral