Air–sea fluxes of oxygenated volatile organic compounds across the Atlantic Ocean

Abstract

Abstract. We present air-sea fluxes of oxygenated volatile organics compounds (OVOCs) quantified by eddy covariance (EC) during the Atlantic Meridional Transect cruise in 2012. Measurements of acetone, acetaldehyde, and methanol in air as well as in water were made in several different oceanic provinces and over a wide range of wind speeds (1-18 m s −1 ). The ocean appears to be a net sink for acetone in the higher latitudes of the North Atlantic but a source in the subtropics. In the South Atlantic, seawater acetone was near saturation relative to the atmosphere, resulting in essentially zero net flux. For acetaldehyde, the two-layer model predicts a small oceanic emission, which was not well resolved by the EC method. Chemical enhancement of air-sea acetaldehyde exchange due to aqueous hydration appears to be minor. The deposition velocity of methanol correlates linearly with the transfer velocity of sensible heat, confirming predominant airside control. We examine the relationships between the OVOC concentrations in air as well as in water, and quantify the gross emission and deposition fluxes of these gases.

Technical Note: A fully automated purge and trap GC-MS system for quantification of volatile organic compound (VOC) fluxes between the ocean and atmosphere

“…Ledyard and Dacey, 1994;Quack et al, 2004;Jones et al, 2009) or via online equilibrator techniques with analysis by pre-concentration GC-MS or chemical ionisation mass spectrometry (Saltzman et al, 2009;Beale et al, 2011;Kameyama et al, 2014). Equilibrator techniques include Weiss-type (Johnson, 1999;Butler et al, 2007;Kameyama et al, 2010), which employs direct contact between the liquid and gas phases, or membrane-type (Groszko and Moore, 1998;Loose et al, 2009;Yang et al, 2014), which physically separates the phases, with the analytes able to pass through the gas permeable membrane. The latter offers the advantage of reduced water vapour in the gas phase, especially if a hydrophobic membrane is used.…”

Air‐sea exchange of methanol and acetone during HiWinGS: Estimation of air phase, water phase gas transfer velocities

“…[] and Yang et al . [] measured the air‐sea acetone flux by EC and found the higher‐latitude oceans to be net sinks of atmospheric acetone.…”

Estimation of bubble-mediated air–sea gas exchange from concurrent DMS and CO<sub>2</sub> transfer velocities at intermediate–high wind speeds

“…Volatile organic compounds (VOCs) such as isoprene, acetone and acetaldehyde alter the oxidising capacity of the troposphere (Carpenter et al, 2012). The solubility differences between these VOCs mean that their exchange is controlled to differing degrees by processes on the water and air side of the air-sea interface (Yang et al, 2014). Many of the factors influencing air-sea gas exchange will be altered by future changes in climate, ocean circulation and biology.…”