Document Type
Article
Publication Title
Biogeosciences
Publisher
European Geosciences Union
Publication Date
2011
Volume
8
Abstract
Conventionally, measurements of carbon isotopes in atmospheric CO2 (δ13CO2) have been used to partition fluxes between terrestrial and ocean carbon pools. However, novel analytical approaches combined with an increase in the spatial extent and frequency of δ13CO2 measurements allow us to conduct a global analysis of δ13CO2 variability to infer the isotopic composition of source CO2 to the atmosphere (δs). This global analysis yields coherent seasonal patterns of isotopic enrichment. Our results indicate that seasonal values of δs are more highly correlated with vapor pressure deficit (r = 0.404) than relative humidity (r = 0.149). We then evaluate two widely used stomatal conductance models and determine that the Leuning Model, which is primarily driven by vapor pressure deficit is more effective globally at predicting δs (RMSE = 1.6‰) than the Ball-Woodrow-Berry model, which is driven by relative humidity (RMSE = 2.7‰). Thus stomatal conductance on a global scale may be more sensitive to changes in vapor pressure deficit than relative humidity. This approach highlights a new application of using δ13CO2 measurements to validate global models.
DOI
10.5194/bg-8-3093-2011
Recommended Citation
Ballantyne, Ashley P.; Miller, J. B.; Baker, I. T.; Tans, P. P.; and White, J. W. C., "Novel Applications of Carbon Isotopes in Atmospheric CO2: What Can Atmospheric Measurements Teach Us About Processes in the Biosphere?" (2011). Ecosystem and Conservation Sciences Faculty Publications. 1.
https://scholarworks.umt.edu/decs_pubs/1
Creative Commons License
This work is licensed under a Creative Commons Attribution 3.0 License.