Gas Analyzers for Cap Verde - Air and Climate - Air Monitoring and Testing
An Aero-Laser AL5001 instrument for the measurement of carbon monoxide mixing ratios in background air has been installed at the National Centre for Atmospheric Science (NCAS) Cape Verde Atmospheric Observatory (CVAO) since October 2006 and there are no plans for the measurements to stop in the foreseeable future. At the University of York we also have an AL5002 instrument which is used for shorter deployments (e.g. for NAMBLEX and OP3 and has in the past been used as a back-up for both the Cape Verde system and the FAAM aircraft system.
The aim of the project is to monitor the background concentration of CO (along with other trace gases) in the tropical marine boundary layer, to gain increased understanding of the oxidation capacity in this region. The CVAO site is a “Global” Global Atmospheric Watch site which means that it meets the requirements to provide data required to address environmental issues of global scale and importance.
Some of these requirements include the following:
- The station location is regionally representative and is normally free of the influence of significant local pollution sources.
- There are adequate power, air conditioning, communication and building facilities to sustain long term observations with greater than 90% data capture (i.e. <10% missing data).
- The GAW CO observation made is of known quality and linked to the GAW CO Primary Standard.
CO data is presently submitted in near-real-time to the MACC (Monitoring Atmospheric Composition and Climate) project which is part of the European GMES (Global Monitoring for Environment and Security) programme. The concentration of CO in the marine boundary layer is mainly controlled by the hydroxyl radical (OH) concentration. Deviations occur as a result of long-range transport from more polluted areas and the occasional biomass burning input from the Canary Islands.