Ten day back trajectory calculations made using the FLEXPART model initiated from Cape Verde Atmospheric Observatory four times a day to show the origins of the air arriving at the observatory and support the analysis of the observations. 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 observatory is based on Calhau Island of São Vicente, Cape Verde 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.