Equipping a profiling float with a novel NDIR Carbon Dioxide sensor in the Eastern Tropical North Atlantic
Researchers from Germany and Cape Verde fitted an oceanographic profiling float (i.e. able to adjust internal buoyancy to either float or sink in the water column) with a Non-Dispersive Infrared (NDIR) carbon dioxide (CO2) sensor, as well as with an oxygen (O2) sensor, to determine the feasibility of combining these two sensors to collect continuous measurements of both gases. The float was deployed near the Cape Verde Ocean Observatory (CVOO) on four separate occasions between November 2010 and June 2011.
Despite the relatively slow sensor response time, the pCO2 data collected were reliable and a comprehensible drift pattern allowed the researchers to easily account for any sensor drift. The combination of CO2 and O2 sensors was found to be feasible and collected data with accuracy similar to that of a more typical but heavier set up. Remarkably, the large changes in pressure and temperature during short-interval upcasts (~1.5 h) of the float did not cause any significant sensor drift.
All-in-all, this set up appears to be feasible for continuous in situ measurements of CO2 and O2 profiles in the ocean.
Fiedler et al. (2013), “In Situ CO2 and O2 Measurements on a Profiling Float”