GoAmazon Terrestrial Ecosystem Science Research

 

Authors

Jeffrey Chambers — Lawrence Berkeley National Laboratory
Kolby Jeremiah Jardine — Lawrence Berkeley National Laboratory
Jennifer A Holm — Lawrence Berkeley National Laboratory
Margaret S. Torn — Lawrence Berkeley National Laboratory
Niro Higuchi — National Institute of Amazonian Research
Antonio Ocimar Manzi — Instituto Nacional de Pesquisas da Amazonia

Category

ARM Infrastructure

Description

The overall goal of the Green Ocean Amazon (GoAmazon) project is to advance a mechanistic understanding of how land-atmosphere processes affect tropical hydrology and climate. One critical terrestrial component of these interactions is the emission of biogenic volatile organic compounds (BVOCs) from Amazon forests, which serve as cloud condensation nuclei (CCN) precursors that influence precipitation dynamics, and modify the quality of incoming light for photosynthesis. However, our ability to represent these coupled biosphere-atmosphere processes in Earth system models (ESMs) is constrained by an extremely poor understanding of the identities, quantities, and seasonal patterns of BVOC emissions from tropical forests. Moreover, we are further limited by our incomplete mechanistic understanding of leaf-level and understory-to-canopy emissions of BVOCs, and canopy responses to changes in light quality. Thus, this GOAmazon Terrestrial Ecosystem Science (TES) project is evaluating the strengths and weaknesses of leaf-level BVOC emission algorithms for forests near Manaus, and conducting targeted field studies designed to fill knowledge gaps toward improving the models and testing a few key hypotheses. We are currently exercising the Model of Emissions of Gases and Aerosols from Nature (MEGAN), which comprises the BVOC submodel of the community Earth system model (CESM), to explore sensitivities with respect to plant-BVOC-aerosol-cloud relationships, and how these vary with factors associated with a warming climate. Based on that analysis, a combination of field observations and experiments are being carried out to test existing parameterizations and algorithm structures, and the models will be modified as needed to improve BVOC emission simulations. Changes in the atmospheric light environment brought about by varying aerosol loading and cloud properties, and related responses of forest tree ecophysiology and BVOC production processes, are also being explored. Project studies are addressing key questions on mechanistic controls over landscape-scale tropical forest BVOC emissions, and driving factors that are expected to change with a warming climate. This poster will highlight current advances from our field studies in forests north of Manaus, Brazil, and the modeling studies that are being carried out synthetically with those field studies.

Lead PI

Jeffrey Chambers — Lawrence Berkeley National Laboratory