This schematic shows how greenhouse gas measurements are made for the Total Carbon Column Observing Network at NIWA's Lauder Atmospheric Research Station in Central Otago, New Zealand.
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At Lauder Atmospheric Research station, an in situ air gas analyser sits by a Fourier Transform spectrometer. Together, these two instruments give precise and accurate measurements of total column amounts and surface concentrations of important greenhouse gases.
The ground-based total column measurements are calibrated to the World Meteorological Organization reference scale for greenhouse gases using aircraft measurements. These calibrated ground-based measurements are then used to validate and calibrate space-based total column measurements made by GOSAT, the Greenhouse Gases Observing Satellite (Image: Erika Mackay, NIWA).