Cape Verde Atmospheric Observatory (CVAO)

The Cape Verde Atmospheric Observatory (CVAO) exists to advance understanding of climatically significant interactions between the atmosphere and ocean and to provide a regional focal point and long-term data. The CVAO is located on São Vicente, one of the Cape Verde Islands, about 800 km west of the African continent. It is located at 16.848N, 24.871W, in the tropical Eastern North Atlantic Ocean, a region which is data poor but plays a key role in atmosphere-ocean interactions of climate-related and biogeochemical parameters including greenhouse gases. It is an open-ocean site that is representative of a region likely to be sensitive to future climate change, and is minimally influenced by local effects and intermittent continental pollution.

The MPI-BGC flask record of the greenhouse gases carbon dioxide (CO2), methane (CH4 ) and nitrous oxide (N2O), as well as their isotopic composition and other trace gases provides important information on changes in the global greenhouse gas budgets and the underlying processes since 2007. — The MPI-BGC flask record of the greenhouse gases carbon dioxide (CO₂), methane (CH₄ ) and nitrous oxide (N₂O), as well as their isotopic composition and other trace gases provides important information on changes in the global greenhouse gas budgets and the underlying processes since 2007.

The MPI-BGC flask record of the greenhouse gases carbon dioxide (CO₂), methane (CH₄ ) and nitrous oxide (N₂O), as well as their isotopic composition and other trace gases provides important information on changes in the global greenhouse gas budgets and the underlying processes since 2007.

CVAO was founded in 2007 as international cooperation between the Max Planck Institute for Biogeochemistry (MPI-BGC, Jena, Germany), the Leibniz Institute for Tropospheric Research (TROPOS, Leipzig, Germany), UK SOLAS (University York, UK), and the Instituto Nacional de Meteorologia e Geofisica (INMG) of the Republic of Cabo Verde. Since then, the station has been part of the MPI-BGC flask network, which analysis of the mixing ratios of CO₂, CO, CH₄, N₂O, H₂ and SF₆. In addition, measurements of the isotopic composition of CO₂ (¹³C/¹²C and ¹⁸O/¹⁶O), as well as O₂/N₂ and Ar/N₂are performed. Since November 2011, real-time N₂O (Nitrous Oxide) and CO (Carbon Monoxide) concentrations have been simultaneously and continuously measured using an Off-Axis Integrated-Cavity Output Spectroscopy (OA-ICOS) analyser (Los Gatos Inc). In November 2012, a Greenhouse Gas Analyser (GGA) using the same fundamental measuring technique was added and placed in series to measure CO₂ (Carbon Dioxide) and CH₄ (Methane) concentrations. Both devices are configured to sample at a frequency of 1Hz and both have the precision and accuracy to conform to measurement recommendations as defined by Global Atmosphere Watch (GAW). Data from the station are routinely published via CEDA.

At CVAO, the University of York provides additional trace gas measurements, supported by the Natural Environmental Research Council (NERC) through the National Centre for Atmospheric Science (NCAS) Atmospheric Measurement & Observation Facility (AMOF) that are traceable to international calibration scales. The Leibniz-Institut für Troposphärenforschung, Leipzig, Germany (TROPOS) measure various characteristics of aerosol. Collaboration is also with the Instituto Nacional de Meteorologia e Geofísica, São Vicente (INMG), who provide logistical support and employ staff at the CVAO. The sister ocean site is a partnership of the Instituto Nacional de Desenvolvimento das Pescas, São Vicente (INDP), and the Leibniz-Institut für Meereswissenschaften, Kiel, Germany (IfM-GEOMAR Kiel). Scientific activities at both sites are coordinated in collaboration with the above institutions.

Thanks to the funding of research infrastructures with the ACTRIS-D project of the BMBF's National Roadmap, the German share of the CVAO observatory can now be renewed and expanded. A photovoltaic system and a new research building will be constructed for this purpose. The research building will significantly improve the working possibilities at the CVAO in the very near future and thus lay the foundation for the continuation of the complex time series investigations at the CVAO for the next two decades.