The Effects of Environmental Variability and Experimental Error in Parameterizing Air-Sea Fluxes

Advances in techniques for measuring air-sea fluxes have resulted in several new oceanic data sets of oceanic gas fluxes. In addition, novel experimental methodologies and detailed microphysical process studies have provided new information concerning the fundamental mechanisms controlling air-water gas exchange. These field and laboratory data have been used in developing and testing air-sea gas exchange dependencies and have allowed commonly used conceptual models to be tested. However, even with the advances in the understanding of the process and the additional experimental capabilities, variability in both laboratory and field data as a function of a particular variable characterizing the major forcing functions (e.g., wind stress) has made development of a robust method for parameterizing the gas transfer velocity difficult. In some cases the scatter in the data from a particular experiment is large enough that it is not possible to choose between relations having different functional forms. In other cases, parameterizations of the gas transfer velocity developed or tuned using data from a particular experiment have been unable to accurately predict transfer velocities measured during different experiments.

Using recent field and laboratory results, the dominant processes controlling air-water gas exchange will be identified. These data will also be used to estimate how variability in the underlying processes contribute to the observed scatter in the measured fluxes and transfer velocities. Finally, the effect these uncertainties have on constraining the air-sea gas transfer velocities will be discussed in relation to how this affects the goal of developing a robust method for predicting air-water gas transfer rates from a small suite of relatively easily measured environmental and physico-chemical parameters.