Monitoring the planetary pulse through measurements and modeling of global greenhouse gas distributions

As exemplified by the iconic Mauna Loa carbon dioxide record (a.k.a. the "Keeling Curve"), long-term time series of atmospheric greenhouse gas mole fractions and their isotope ratios are fundamental building blocks in our understanding of global biogeochemistry. Their seasonal and interannual variations constrain oceanic, land biosphere, and anthropogenic sources and sinks. In doing so, these measurements provide important checks on our understanding of feedbacks between the climate and biosphere. A classic example of this is the seminal work of Tans et al. (1990) in which the spatio-temporal distribution of atmospheric carbon dioxide was used to show conclusively the presence of large carbon sinks in the terrestrial biosphere (likely in Northern Hemisphere forests). In this presentation, we will provide additional examples of how time series and spatial gradients of atmospheric greenhouse gases, interpreted both directly and through three-dimensional models of atmospheric transport, can be used to improve our understanding of the present-day and future carbon cycle.