GEOSCAN Search Results: Fastlink


TitleThe Role of Remote Sensing in Determining Multiple-Year Carbon Absorption by Canadian Forests
AuthorLiu, J; Chen, J M; Cihlar, J; Chen, WORCID logo
SourceIEEE 1999 International Geoscience and Remote Sensing Symposium, Hamburg, Germany, 28 June - 02 July; 1999.
Alt SeriesEarth Sciences Sector, Contribution Series 20042851
SubjectsNature and Environment
AbstractCarbon absorption by vegetation, commonly referred as the net primary productivity (NPP), is one of important components in terrestrial carbon budget which affects climate change. Among different approaches determining NPP, ecophysiologically-based models have advantages of (1) being scientifically sound and therefore potentially reliable, (2) the ability to handle interactions and feedbacks of different processes, (3) the flexibility to describe details of biological processes under variety of conditions. However, application of models of this type has been hindered by the data availability and the need for temporal and spatial scalings, especially over large areas and for moderate or high resolutions.

At Canada Centre for Remote Sensing, efforts are made to develop an ecophysiologically-based model to simulate NPP over Canadian landmass at moderate resolutions (~1 km). An instantaneous leaf level photosynthesis model is scaled up temporally and spatially to the entire canopy at daily step. Remote sensing techniques provide two of most important driving variables to the model: land cover type, and leaf area index (LAI). The information on land cover type is critical in determining different functionlities of the various species, while LAI strongly affects almost all components of the model, including radiation absorption, photosynthesis, respiration, transpiration, rainfall interception and soil water balance. In the model, dynamic change in vegetation detected by remote sensing is immediately considered. Timely remotely-sensed data are critical to accurate NPP calculations.

Multiple-year satellite-derived data and ancillary climate and soil data are compiled to simulate interannual carbon absorption by Canadian boreal forests (from 1994-96). The results are validated with biomass data and tower flux measurements in several locations in Canada. The interannual variation of carbon absorption is analyzed for different vegetation type, weather and soil conditions.


Date modified: