As of 2010, the globally averaged concentration of carbon dioxide (CO 2 ) in the atmosphere has risen by 109 ppm (WMO GHG report, 2011) from its pre-industrial concentration of 280 ppm (Jacob, 1999). Temperature records show that the globally averaged annual mean surface air temperature has been increasing since the industrial revolution (IPCC 4 th assessment report). This is in part due to the rising concentration of greenhouse gases (such as CO 2 ) in the atmosphere. The Intergovernmental Panel on Climate Change (IPCC) 4 th assessment report predicts the frequency of severe weather events will increase as the temperature increases. Therefore, it is important to monitor the concentration of CO 2 in the atmosphere.
The Total Carbon Column Observing Network (TCCON) is a network of ground-based Fourier transform infrared (FTIR) spectrometers that measures solar absorption spectra. Using the GGG software package, total column abundances of CO 2 are retrieved from spectra. The goal of TCCON is to provide accurate measurements of CO 2 in order to identify regional sources and sinks of CO 2 (Wunch et al., 2011). The Eureka site, located on Ellesmere island (Nunavut, Canada), is the most northern TCCON site making CO 2 measurements since 2010. In this talk I will discuss how TCCON measurements of CO 2 are made at Eureka and how phenomena such as spectral line mixing effect the measurements.