HR: 17:40h
AN: B24C-07    [Abstracts]
TI: Analysis of eco-hydrological control and feedback using data-derived entropic process networks
AU: * Ruddell, B L
EM: bruddell@uiuc.edu
AF: University of Illinois at Urbana-Champaign, Hydrosystems Lab 205 North Mathews Avenue, Urbana, IL 61801, United States
AU: Praveen, K
EM: kumar1@uiuc.edu
AF: University of Illinois at Urbana-Champaign, Hydrosystems Lab 205 North Mathews Avenue, Urbana, IL 61801, United States
AB: We hypothesize that plant ecosystems form self-organizing systems on the landscape which function to control their immediate surroundings towards the end of improving the efficiency of community carbon assimilation. Self- organization is difficult to define, but the concept requires the presence of feedbacks. Flows of control and feedbacks may be studied using network theory. This research uses entropy-based statistics of information flow to render the eco-hydrological system as a process network empirically derived from multivariate timeseries datasets. The resulting process network is analyzed to identify ecosystem controls and feedbacks and to separate different modes of system behavior. This approach is applied to the central corn belt eco-region using FLUXNET eddy-covariance timeseries data. Results indicate that plant respiration is a dominant controller of the interaction in the network of variables, including CO2 flux and sensible heat flux under well-watered conditions, and latent heat flux (but not CO2 flux) under drought conditions. Respiration is not controlled directly by other processes in the network, indicating that respiration is an independent (information-driven) mechanism of control by plants. Under drought conditions the ecosystem loses its ability to control CO2 assimilation through respiration, in agreement with the Ball-Berry model. CO2 flux inhabits a control feedback loop via latent and sensible heat flux, precipitation and cloud conditions, suggesting that carbon assimilation activity forms the basis of a self-organizing system spanning the Atmospheric Boundary Layer. Our finding that plants regulate their environment and CO2 uptake by modifying respiration, and that carbon assimilation feeds back on itself via atmospheric processes, supports the hypothesis that this ecosystem is self-organizing.
DE: 1813 Eco-hydrology
DE: 1843 Land/atmosphere interactions (1218, 1631, 3322)
SC: Biogeosciences [B]
MN: 2007 Fall Meeting