Estimation of the seasonal cycle of greenhouse gas fluxes from the terrestrial biosphere: Status and challenges for more mechanistic understanding
- Johnson Controls World Services, Moffett Field, CA (United States)
The most radiatively active greenhouse gases (GHG) in the atmosphere have significant exchange fluxes with terrestrial ecosystems. Small scale measurements from chamber studies strongly suggest that net emissions of carbon dioxide (CO{sub 2}), methane (CH{sub 4}), and nitrous oxide (N{sub 2}O) each show distinct seasonal patterns in ecosystems throughout the globe. Recent advances in modeling the dynamic climatic, biological, and geochemical controllers of terrestrial GHG fluxes using remote sensing drivers have contributed to a more mechanistic understanding of the role and feedbacks of ecosystems in worldwide budgets than previously provided by simple extrapolation techniques. The CASA (Carnegie-Ames-Stanford Approach) Biosphere formulation is a new process-based model of terrestrial ecosystem biogeochemistry that uses spatially and temporally resolved inputs from global satellite and other land surface data sets. Seasonal carbon cycles are simulated using temperature and moisture scalars together with the vegetation `greenness` index derived from the satellite-borne Advanced Very High Resolution Radiometer (AVHRR). This ecosystem production model is the basis for estimation of major terrestrial GHG fluxes: CO{sub 2} is exchanged with the atmosphere through primary production and soil microbial respiration at an annual rate of approximately 50 billion tons carbon; soil emissions of N{sub 2}O and NO are estimated at 6.1 and 9.7 million tons nitrogen per year, respectively; a methanotrophic soil sink for CH{sub 4} is estimated at 17--30 million tons carbon per year. 105 refs., 8 figs.
- OSTI ID:
- 234034
- Journal Information:
- World Resource Review, Vol. 8, Issue 1; Other Information: PBD: Mar 1996
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
29 ENERGY PLANNING AND POLICY
GREENHOUSE EFFECT
GREENHOUSE GASES
AIR-BIOSPHERE INTERACTIONS
TERRESTRIAL ECOSYSTEMS
MATHEMATICAL MODELS
CARBON DIOXIDE
ECOLOGICAL CONCENTRATION
METHANE
NITROUS OXIDE
NITRIC OXIDE
GLOBAL ASPECTS
SEASONAL VARIATIONS
ENVIRONMENTAL EFFECTS
AIR POLLUTION MONITORING
CARBON CYCLE
RADIOMETERS