A global network of ground-based Fourier transform spectrometers has been founded to remotely measure column abundances of CO_2, CO, CH_4, N_(2)O and other molecules that absorb in the near-infrared. These measurements are directly comparable with the near-infrared total column measurements from space-based instruments. With stringent requirements on the instrumentation, acquisition procedures, data processing and calibration, the Total Carbon Column Observing Network (TCCON) achieves an
accuracy and precision in total column measurements that is unprecedented for remotesensing observations (better than 0.25% for CO_2). This has enabled carbon-cycle science
investigations using the TCCON dataset, and allows the TCCON to provide a link between satellite measurements and the extensive ground-based in situ network
