EM27/SUN spectrometer (COCCON project)
We are participating in the COCCON network, which stands for COllaborative Carbon Column Observing Network.
In 2011, a new type of portable FTIR spectrometer for the measurement of the main greenhouse gases was developed by the Karlsruhe Institute of Technology (KIT), Germany in cooperation with Bruker Optics (Germany). Since 2014, these spectrometers are commercially available under the model designation Bruker EM27/SUN. Column-averaged abundances of carbon dioxide, methane and water vapor can be deduced from the recorded solar absorption spectra. Furthermore, since 2016, a second channel for the measurement of carbon monoxide was incorporated into the existing device and is now optionally available.
The Bruker EM27/Sun Fourier Transform Spectrometer
Presently more than 40 devices are operated around the globe by working groups in Germany, USA, UK, India, Namibia, Japan, China and Mexico. In this short time, the number of devices has already become comparable to the number of stations that are operated within the framework of the TCCON (Total Carbon Column Observing Network) sites. Several working groups have already demonstrated the unprecedented level of performance and stability that is achieved by the mobile EM27/SUN spectrometer [Frey et al., 2015 
].
The excellent performance of the novel device opens up the chance of supporting the current TCCON network. This includes for example an inter-calibration of the TCCON sites using an EM27/SUN spectrometer as travel standard, the observation of localized sources of greenhouse gases using an array of several spectrometers (e.g. metropolitan areas or mining regions), or the operation as station instruments in their own right (especially in regions that are not suitable for TCCON spectrometers) as is the case for us.
At this point, the necessity for complying with common standards becomes apparent. Therefore, a new infrastructure for greenhouse gas measurements using the EM27/SUN spectrometer was initiated by KIT. This emerging network is named COCCON, the COllaborative Carbon Column Observing Network. Several fundamental requirements are covered by this platform:
(1) The definition and maintenance of instrumental standards
(2) The performance verification
(3) A common way of data processing
(4) The data dissemination to the user community
For further information please the COCCON home page.
We hope to have the Bruker EM27/SUN spectrometer operational at the Tropical Remote Sensing Institute before the end of 2020.
TCCON site Map (2019): With the closing of the site in Manaus there are presently no observations available from South America. Cali would also be the only truly tropical site with moderate water vapour opacity due to its notably higher elevation above sea level as compared to Darwin or Ascension.