HR: 09:15h
AN: B51F-06    [Abstracts]
TI: Understanding disturbance impacts on the ecosystem respiration with a continuous monitoring system
AU: * Gamon, J
EM: jgamon@exchange.calstatela.edu
AF: California State Univ., Los Angeles, Department of Biological Sci., Los Angeles, CA 90032 United States
AU: Cheng, Y A
EM: ycheng5@exchange.calstatela.edu
AF: California State Univ., Los Angeles, Department of Biological Sci., Los Angeles, CA 90032 United States
AU: Mao, Z
EM: zmao@calstatela.edu
AF: California State Univ., Los Angeles, Department of Biological Sci., Los Angeles, CA 90032 United States
AU: MacKinney, L
EM: loren_mackinney_52@hotmail.com
AF: California State Univ., Los Angeles, Department of Biological Sci., Los Angeles, CA 90032 United States
AU: Claudio, H
EM: greywolf@ugcs.caltech.edu
AF: California State Univ., Los Angeles, Department of Biological Sci., Los Angeles, CA 90032 United States
AU: Wong, N
EM: newtonwong@yahoo.com
AF: California State Univ., Los Angeles, Department of Biological Sci., Los Angeles, CA 90032 United States
AU: Luo, H
EM: luo@sunstroke.sdsu.edu
AF: San Diego State University, Global Change Research Group, San Diego, CA 92182 United States
AU: Oechel, W C
EM: oechel@sunstroke.sdsu.edu
AF: San Diego State University, Global Change Research Group, San Diego, CA 92182 United States
AB: Respiration is a critical part of ecosystem carbon balance, yet we don't have sufficient ways of directly assessing respiration over large areas for a long time. This study is designed to assess ecosystem respiration rates at a large scale through modeling driven primarily by remotely sensed signals and ecosystem physical properties. The study was conducted at the Sky Oaks Field Station in Northeast San Diego County. This site was unique because it had experienced many disturbances, including extremely drought, wildfire, and ENSO oscillations. This provided a rich set of opportunities for studying perturbing respiratory processes. We have deployed an automated, dual-channel spectrometer mounted on a mobile "Tram system" that provided repeated sampling of the same 100m transect We used optical and thermal measurement to link the different components of the net ecosystem exchange measurement from the adjacent eddy tower. An automatic soil chamber system has been set up to monitor soil CO$_{2}$ fluxes to separate the net ecosystem exchange from the belowground contribution. Along the tram system, a series of soil temperature and soil moisture sensors have been set up to monitor the continuous spatial patterns of soil properties for the soil respiration model. From short-temporal scale measurement, soil temperature alone explained 76% of the variation in soil respiration rate, and soil moisture alone explained 63%, while both variables combined explained 81% of the variation. There was a strong link between normalized difference vegetation index (NDVI) and ecosystem respiration. However, this relationship changes under severe disturbance (e.g. drought and fire). Our goal is to extend the respiration model to larger scales through satellite (e.g. MODIS) remotely sensed signals.
DE: 3360 Remote sensing
DE: 1851 Plant ecology
DE: 1866 Soil moisture
DE: 0315 Biosphere/atmosphere interactions
DE: 0614 Biological effects
SC: Biogeosciences [B]
MN: 2004 AGU Fall Meeting