CO emission from the ocean: An estimation from a basin-wide observation in the Atlantic

Abstract

Carbon monoxide (CO) plays an important role in the atmospheric chemistry and climate by reacting with the hydroxyl radical in the atmosphere. It is emitted to the atmosphere largely by human activities, biomass burning, and airborne production by the oxidation of hydrocarbons. Its oceanic emission is limited but not non-trivial

according to Intergovernmental Panel on Climate Change (IPCC, 2001) CO emits from the ocean by 50 Tg CO/yr which corresponds to about 2% of all CO sources. We estimate the oceanic emission based on the basin-wide observations in the Atlantic. The research was carried out aboard RRS James Clark Ross in September and October of 1998 as a part of the Atlantic Meridional Transect (AMT) research program. The cruise track covered from ~50°N, Grimsby, U.K., to ~50°S, Falkland Islands. During the cruise, we encountered several different oceanographic regimes in the Atlantic, and over 2300 measurements of CO in the surface water and overlying air were made. Dissolved CO was supersaturated everywhere up to ~90 times and oscillates in a diurnal pattern along the cruise track. The amplitude of the diurnal variation appeared to be large in the high chlorophyll region, although that in the high latitudes in the southern hemisphere was low probably due to high wind and the overcast clouds during the cruise. Based on the observations, I estimated the oceanic emission as 4 &#8211

24 Tg CO/yr with a central values of 14 Tg CO/yr which is far lower than the value reported by IPCC(2001).