Ocean-Atmosphere Exchange and Earth-System Biogeochemistry

Abstract

Atmosphere-ocean chemical exchanges exert a significant control on both the gas-phase and particulate composition of the atmosphere. As a consequence, there are close linkages of these exchanges with atmospheric radiative transfer, climate and atmospheric chemistry. Such exchanges are important to human society both because they are fundamental to predictions of future climate forcing and because of an immediate need for science-based assessment of the effectiveness of proposed emission controls and other mitigation strategies. In this article we present a subjective overview of the current state of knowledge related to the exchange of climate-relevant materials including long-lived gases (CO2, N2O), short lived gases including volatile sulphur and halogen-containing compounds, and sea salt. Because of the importance of quantification of air-sea exchanges for short-term control of the concentration of these species in ocean and atmosphere, we also review recent progress and present opportunities related to studies of air-sea gas transfer. Finally we present a range of open questions, promising approaches and major challenges related to the measurement, modelling and understanding of air-sea chemical exchanges. Many of these issues will be addressed within the new global change research program SOLAS (Surface Ocean Lower Atmosphere Study).