The noble gases (helium, neon, argon, krypton, xenon) are dissolved in the ocean at concentrations near equilibrium with the atmosphere, have known physical properties, and are abiotic which makes them excellent tracers of the physical processes that cycle gases in the ocean. In addition, each of the gases has unique properties making them sensitive to different physical processes. For this reason, scientists from Woods Hole Oceanographic Institution and Lamont-Doherty Earth Observatory will use inverse and forward modeling of noble gases to improve our knowledge of the physical processes that control the cycle of gases such as carbon dioxide, oxygen, and nitrogen in the ocean. Specifically, they would address the following three processes: (1) parameterize bubble mediated air-sea gas fluxes from breaking waves; (2) identify the background ocean accumulation of dissolved nitrogen gas from biologically mediated denitrification in the deep ocean; and (3) evaluate the strength of the solubility pump using three ocean models. To accomplish their goal, the researchers plan to compile all available noble gas observations prior to constraining gas cycling via simulations performed using three state-of-the-art ocean circulation estimates based on the Community Earth System Model, the Geophysical Fluid Dynamics Laboratory Coupled Climate Model, and the Estimating the Circulation and Climate of the Ocean data assimilated model. From this modeling effort, the researchers will be able to interpret upper ocean oxygen measurements from autonomous sensors, constrain deep ocean denitrification, and evaluate the solubility pump which is needed to assess the anthropogenic uptake of carbon dioxide.
As regards broader impacts, the scientists will create a version of the transport matrix method for use in graduate student courses. The database of noble gas observations along with data standards and metadata will be made available to the science community, as well as the transport matrices from the Community Earth System Model and Geophysical Fluid Dynamics Laboratory Couple Climate Model 2.1. One postdoc from Woods Hole Oceanographic Institution (WHOI) will be supported by this project. It is anticipated that an undergraduate students will be involved in the study and supported via the WHOI Summer Fellowship Program.