Biogeochemical Argo floats
The addition of biogeochemical sensors to profiling floats has yielded annual cycles of observations in regions that previously were only measured sporadically. I use these measurements to understand net biological production, air-sea gas exchange, the relative roles of biology and physics in setting the large-scale cycles we observe, and much more.
Main takeaway: Newly available biogeochemical observations allow us to answer long-researched questions and ask new questions we never had the tools to consider.
Southern Ocean air-sea carbon dioxide fluxes
Floats deployed by the SOCCOM program are being used to estimate pCO2 throughout the year in the Southern Ocean. We have combined these float estimates with the traditional ship-based measurements to produce new estimates of the Southern Ocean CO2 flux.
Southern Ocean oxygen fluxes
The high density of Argo floats equipped with oxygen sensors in the Southern Ocean made it possible for us to calculate regional air-sea fluxes over a 9 year period. This represents the first time we could resolve seasonal and spatial cycles in the air-sea oxygen flux within a large ocean basin using direct measurements, as opposed to an inversion or other secondary approach.
Main takeaway: Oxygen uptake is up to 2x higher than prior estimates, largely due to new wintertime observations around and underneath the seasonal sea ice. More details…
Air-sea gas exchange
Understanding how gas exchanges between the air and the water and what we can use to estimate this flux is incredibly important to our understanding of upper ocean processes. Air-sea flux parameterizations are used in everything from global climate models to simple box models because it is very difficult to measure the actual air-sea flux and we instead must use something we can measure, like wind speed, and estimate the flux with a parameterization. All of my upper ocean data analyses rely on air-sea flux parameterizations, which is why I am intrigued by testing and improving our understanding these relationships. Bubbles generated by waves and fractured sea ice are two of the factors that I am trying to better understand in my work.
Oxygen sensor calibration
Oxygen is a key ocean variable, but one that is surprisingly hard to measure accurately. I have developed in situ calibration approaches for oxygen optodes and am working to improve our understanding of how these techniques can be used on our growing array of robotic sensor platforms. The beauty of oxygen optodes is that they measure oxygen in both air and water. After demonstrating this in the lab we have used this technique in a mooring-based calibration system and on profiling Argo floats. Air calibration is now incorporated into most newly deployed biogeochemical floats and represents an important component of our ability to accurately measure the ocean. More details…