NGEE-Tropics is a ten-year, multi-institutional project funded by the U.S. Department of Energy (DOE), Office of Science, Office of Biological and Environmental Research (BER). In our current Phase 1 (of three phases), we organized our research into a set of science questions and objectives that allow our researchers to assess what is known about tropical forest ecosystems and how well these processes are represented in models.
Three Overarching Questions
Q1. How do tropical forest ecosystems respond to changing temperature, precipitation, and atmospheric CO2 concentration?
Q2. How do disturbance and land-use change in tropical forests affect carbon, water and energy fluxes?
Q3. How will the response of tropical forests to climate change be mediated by spatial and temporal heterogeneity in belowground processes?
Six Research Objectives
CO2 and Temperature | Tropical forest carbon uptake and allocation in response to rising temperature and CO2 Natural Disturbance | Tropical forest dynamics under natural disturbance regimes
Hydrology | Variability of surface and subsurface water availability to tropical forests across space and time Nutrient Constraints | Nutrient availability and nutrient controls over tropical forest productivity and post-disturbance recovery rates
- Puerto Rico Pilot Study on land use-nutrient cycling interaction
- Manaus Pilot Study on hydrology-carbon interactions from trees to landscapes
- Panama Pilot Study on plant trait filtering along moisture gradients
Pantropical Representative Analysis of Field Sites | Implementation of aTree Mortality Baseline Study across pantropical ForestGEO plots to test new methods and establish a baseline for long-term observations of tree mortality.
Tree Mortality Baseline Study | Implementation of initial data collection at these core FO2 sites will provide critical baselines that fill known high-priority knowledge gaps
Modeling and Integration Framework
The grand deliverable of NGEE-Tropics is the development of a representative, process-rich tropical forest ecosystem model, extending from bedrock to the top of the vegetative canopy- atmosphere interface, in which the evolution and feedbacks of tropical ecosystems in a changing climate can be modeled at the scale and resolution of a next generation Earth System Model grid cell. We call this model ACME-FATES (Accelerated Climate Modeling for Energy-Functionally Assembled Terrestrial Ecosystem Simulator).
Achieving both the NGEE-Tropics grand deliverable and Research Objectives requires coordinated model development activities that leverages existing, ongoing, and novel approaches to representing the dynamics of tropical forests. To accomplish this, we have defined a set of specific Modeling Objectives:
- Tropical model testbed for comparing observations against model predictions and quantifying sources of model uncertainty
- Methods to predict and test shifts in plant trait distributions in response to environmental perturbations
- Spatial scaling framework to allow modeling of fine-scale environmental heterogeneity and its role in governing ecosystem function
- Modeling framework for managing model complexity
Data Synthesis and Management Framework
NGEE-Tropics requires the use of diverse existing and new data collections, and the generation of data products that are consistent across our Objectives. We are developing a NGEE-Tropics Data Synthesis and Management Framework to include infrastructure for defining and building data synthesis and analysis products, as well as model parameters and benchmarks. The data team will also develop a portal that provides access to community data repositories and project data, and enables broad usage through data sharing, while providing a well-curated and accessible project data repository. The data portal is expected to become a key resource in fostering strong partnerships with the broader tropical forest and ESM research communities.
By teaming with our Research Objective and Modeling groups and building common infrastructure, the data team is helping obtain existing data sets, perform QA/QC and transformations of data as needed, implement synthesis-product-generation pipelines, and manage the underlying data. See our Data Objectives below:
- Develop an agile infrastructure for defining and building data synthesis and analysis products, including translation for model parameterization and benchmarking
- Develop a portal that provides unified access to community data repositories and project data and that enables broad usage through data sharing
- Develop a well-curated, accessible repository for NGEE-Tropics data
ModEx Approach
Fundamental to our approach is the recognition that developing models to produce robust predictions of tropical forest response to global change will require strong collaborations between modeling and measurement scientists, as exemplified by the concept of model-experimental integration (ModEx). ModEx requires that experiments and observational studies are designed to address specific modeling gaps, and that evaluation of those new model structures inform additional measurement activities in an iterative manner (DOE 2012). This approach will be central to the NGEE-Tropics enterprise, focused on those processes where uncertainties most strongly control model response, and are most critical for determining the fate of the tropical forest carbon sink over the next 100 years.
