CARBON-MONOXIDE GRADIENTS IN THE MARINE BOUNDARY-LAYER OF THE NORTH-ATLANTIC OCEAN

We present an observational data set that suggests that the ocean sour ce of carbon monoxide (CO) may influence the atmospheric CO concentrat ion in the marine boundary layer (MEL). Atmospheric CO concentration g radient data obtained during the 1992 Atlantic Stratocumulus Transitio n Experiment Marine Aerosol and Gas Exchange (ASTEX/MAGE) show signifi cantly (range of 2-47 ppbv, average of 15 ppbv) more CO at altitudes o f 0.05 to 0.5 m above sea level as compared to 10 m above sea level. T he seawater CO concentrations needed to support the fluxes obtained fr om an atmospheric gradient calculation are much higher than generally reported in the literature. However, studies of CO production by Jones and Amador (1993) and data from Seller (1978) suggest the possibility that CO production and the resultant flux to the MBL could be 1-2 ord ers of magnitude higher than currently estimated using seawater pumped from depths of 4-10 m below the sea-air interface. We infer that the surface ocean production and sea-air exchange of photochemically produ ced trace gases such as CO may participate in physical, chemical and b iological processes on vastly different spatial and temporal scales th an those inherent to more stable species such as CO2.