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, Journal Name: World Resource Review Journal Issue: 1 Vol. 8; ISSN WRRVE5; ISSN 1042-8011
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
54 ENVIRONMENTAL SCIENCES
AIR POLLUTION MONITORING
AIR-BIOSPHERE INTERACTIONS
CARBON CYCLE
CARBON DIOXIDE
ECOLOGICAL CONCENTRATION
ENVIRONMENTAL EFFECTS
GLOBAL ASPECTS
GREENHOUSE EFFECT
GREENHOUSE GASES
MATHEMATICAL MODELS
METHANE
NITRIC OXIDE
NITROUS OXIDE
RADIOMETERS
SEASONAL VARIATIONS
TERRESTRIAL ECOSYSTEMS