HR: 1340h
AN: B33D-1590    [Abstracts]
TI: Water limitation of net primary productivity and the link to Water Use Efficiency
AU: * Verstraeten, W W
EM: willem.verstraeten@biw.kuleuven.be
AF: Geomatics Engineering, Katholieke Universiteit Leuven, Celestijnenlaan 200E, Heverlee, VL BE-3001, Belgium
AU: Veroustraete, F
EM: frank.veroustraete@vito.be
AF: Centre for Remote Sensing and Earth Observation Processes, Flemish Institute for Technological Research, Boeretang 200, BE-2400, VL BE-3001, Belgium
AB: Monitoring, understanding and modeling carbon emission and fixation fluxes in combination with water demands are key variables to guide climate change stakeholders in the application of mitigation strategies since a strong coupling between the carbon and the hydrological cycle is observed. Water Use Efficiency (WUE) is the ratio of the net amount of carbon uptake by vegetation and the amount of water lost by evapotranspiration. WUE is the biogeochemical link between the carbon and hydrological cycles. Hence, the use of WUE as a proxy for the carbon and water cycle linkage is a promising tool to foster a better understanding and estimation of the impact of climate on terrestrial ecosystem. Field-experiments and point-simulations for a specific ecosystem allow to accurately estimate plant WUE. They however face scientists with the difficulty of scaling up WUE from the local to the regional scale. Remote sensing represents a technique providing spatial and temporal explicit datasets at regional to global scales and hence it is a promising approach to assess regional to global WUE by the joint estimation of net primary productivity (NPP) of plants and evapotranspiration at various spatial and temporal scales. In this study we present results on water limitation impact on ecosystem carbon uptake and release using an enhanced C-Fix model compared with validation data collected at EUROFLUX sites. It is demonstrated that if the water household of a terrestrial ecosystem is taken into account the balance between NPP and anthropogenic carbon emissions (ACE) for the European continent is changed quite significantly. Using water limited NPP at the country scale, we can reveal that many nations such as Czech/Slovakia, Hungary, Ireland, Italy and Switzerland change their NPP-ACE balance from positive to negative. These results were obtained with data acquired for Europe in 1997.
DE: 0428 Carbon cycling (4806)
DE: 0480 Remote sensing
DE: 0496 Water quality
SC: Biogeosciences [B]
MN: 2007 Fall Meeting