Kenneth Davis Department of Meterology 512 Walker Building University Park, PA 16802 (814) 863-8601 davis@meteo.psu.edu
David Hollinger USDA Forest Service 271 Mast Rd. Durham, NH 03824
Bev Law 328 Richardson Hall Oregon State University Corvallis, OR 97330
J. William Munger Division of Engineering and Applied Science 24 Oxford Street Cambridge, MA 02138
This research design response addresses both of the NEON Science Challenges. The general science question is: How will the carbon and water cycle of the terrestrial ecosystems of the United States, in particular exchanges between ecosystems and the atmosphere, respond to future changes in climate, land use/vegetation cover, soil/hydrologic status, and environmental chemistry, and thus feed back to future climatic change?
The AmeriFlux network is a collection of research sites dating from 1992 that have employed and perfected much of the technology envisioned for the NEON Advanced BioMesoNet Towers. The AmeriFlux network was formed to address scientific questions that broadly and fundamentally overlap with those of NEON. The AmeriFlux consortium of existing research sites are well suited to contribute to the proposed science challenge and contribute to NEON’s broader scientific endeavor.
Here we suggest an overall observational strategy for the science question posed, suggest how existing AmeriFlux sites can be incorporated into this observational strategy, and propose a structure for periodically evaluating and updating the network design.
Factors governing the carbon and water cycles that will be evaluated within the proposed research framework include: a) Climate: (Temperature; Precipitation; Radiation); b) Land Use/Vegetation Cover: (Wild lands, with varying degrees and types of natural disturbance including fire, wind, and invasive species; ‘Natural’ ecosystems with varying levels of management e.g. forests vs. thinning, clearcut, time since harvest and grasslands vs. grazing, grazing intensity; Agro-ecosystems); c) Soil/Hydrologic State: (Soil moisture, Soil texture, porosity, Soil temperature/duration of frozen soils, Depth of water table, Slope, Location within watershed); and d) Environmental chemistry: (Nitrogen deposition, Atmospheric CO2, Atmospheric ozone, Soil nutrients). The chosen land-use and disturbance factors are typical of those found in a domain.
These factors will be evaluated through a nested observational design using advanced biomesonet towers and reloctable tower systems, integrated with airborne and satellite remote sensing, and modeling of ecosystem processes and feedbacks to climate. Observations of trends across nested gradients will be translated into ecosystem models with substantially improved capacity for predicting future ecosystem-atmosphere exchanges of carbon, water and energy.
We propose that certain AmeriFlux sites become core or gradient sites within the NEON network. These sites would be those that 1) have proven suitable for the scientific tasks proposed here, and 2) are willing to adopt a role within the NEON structure. It will be of great advantage to NEON to build upon and exploit long time series (up to 14 years) of ecosystem-atmosphere flux and biology data. The AmeriFlux sites proposed have relevant infrastructure and expertise, are suitable for micrometeorology, have undergone extensive QC/QA, and have proven records of scientific productivity. The inclusion of these sites in NEON will greatly enhance the prospect of NEON meeting its scientific goals on time and within budget. In turn, the NEON will provide a path to a strong centralized network necessary for this research endeavor to succeed.