Goal Inverse modeling identifies carbon sources and sinks, and coupled with a planetary transport model, generates predicted CO2 concentrations. Ideally, the model is adjusted so that the predicted flux measurements best match those measured at various locations around the globe.
Components Observed Atmospheric Concentrations of CO2 - Spatiotemporal concentrations (ppm) of CO2
Observed Sea Surface Concentrations of CO2 General Circulation Model
Fossil-Fuel-Based Emissions (Confidence: High) Land Use Change (Confidence: Low) Terrestrial Ecosystem Response to Elevated CO2 (Confidence: Low) Terrestrial Sink (Confidence: Low) Ocean Sink (Confidence: Low) *Confidence refers to amount, temporal pattern, and spatial location
Geophysical Monitoring for Climate Change (GMCC) Network Based on flask measurements 20 cites since 1980
Atmospheric CO2 Sampling Sites
Atmospheric CO2 Concentration
Oceanic Observations Transect Sampling, some data gaps in Indian and Southern Ocean- extrapolation based on Sea Surface Temperatures Oceans divided into 2o x 2o grids, and mean pCO2 is calculated for the periods (January through April) and (July through October)
Working Formula for F (CO2 flux across air-sea interface):
Oceanic CO2 Calculations
Oceanic CO2 Fluxes
Oceanic CO2 Fluxes
Transport Model 3-D General Circulation Model (GCM) from Goddard Space Flight Center, NASA Seasonal, diurnal
Transport Model (vs. Observed)
Modeled Atmospheric CO2 Concentrations
Modeled Fluxes
Modeled Fluxes
Modeled NPP
Modeled CO2 Sources and Sinks Atmospheric CO2 increases about 3 Gt C/yr - ocean sink is largest at equator
- must be a larger northern terrestrial sink
El Nino and La Nina cycles changes fluxes
Which Transport Model to Use? Many different transport models can give different results Underscores uncertainty in inverse model results Transcom 3 Project (Gurney, 2002) seeks to compare the outcome from various models
Which Transport Model to Use?
Which Transport Model to Use?
El Nino and La Nina (increased biomass burning), changes in NPP Volcanic Eruptions (e.g., Pinatubo- changes in NPP from sunlight limitations) Temperature and humidity affect microbial respiration (soil respiration increases at higher temperatures)
References I.G. Enting, C.M. Trudinger, R..J.A. Francey (1995) A synthesis inversion of the concentration of 13C of atmospheric CO2. Tellus B 47, 35-52. S. Fan, et al., (1998) A large terrestrial carbon sink in North America implied by atmospheric and oceanic carbon dioxide data and models. Science 282, 442-446. K. R. Gurney et al., Towards robust regional estimates of CO2 sources and sinks using atmospheric transport models, Nature 415, 626 (2002). C. Roedenbeck, S. Houweling, M. Gloor, and M. Heimann (2003) CO2 flux history 1982–2001 inferred from atmospheric data using a global inversion of atmospheric transport, Atmos. Chem. Phys., 3, 1919–1964. P. P. Tans, I. Y. Fung, T. Takahashi, (1990) Observational Constraints on the Global Atmospheric CO2 Budget, Science 247, 1431-1438.
Dostları ilə paylaş: |