-Contributed by Sarah Gille
“Air-Sea Fluxes for the Southern Ocean: Strategies and Requirements for Detecting Physical and Biogeochemical Exchanges” was the focus of a workshop held in Frascati, Italy, from 21-23 September 2015. The workshop attracted a total of 48 participants. Together the Southern Ocean Observing System (SOOS), the World Climate Research Programme (WCRP), the European Space Agency (ESA), the US National Oceanic and Atmospheric Administration (NOAA), and US CLIVAR provided sponsorship for the workshop, which was hosted by the European Space Research Institute (ESRIN).
Air-sea flux measurements pose significant challenges in the Southern Ocean because of the remote location, high sea state, and icing conditions of the region. Recent technological developments have given new hope to the prospects for obtaining high-quality flux observations in high-latitude conditions. The workshop considered a broad range of these new technologies, including wave gliders, unmanned aerial vehicles, aircraft observations, new moorings (the Southern Ocean Flux Station, the Ocean Observatories Initiative moorings in the southeast Pacific and the Argentine Basin), and shipboard flux covariance measurements with the eventual possibility correcting for airflow distortion around the ship. In situ observations are critical but need to be interpreted in a broader context that can come from satellite observations and from reanalysis or state estimation.
Three specific recommendations emerged from the workshop. First was the importance of including air-sea heat and momentum fluxes in the list of Essential Climate Variables, with specific requirements for accuracy and precision of measurements. Second participants recommended development of a pilot study focused on a targeted measurement campaign in a compact region near a mooring, along with related satellite data assessment and assimilation efforts. The objective to target a small region will allow evaluation of eddy-scale spatial variability in fluxes, since these scales play a significant role in determining the representativeness and underlying physics behind individual flux observations. Finally, participants supported the development of a SOOS Capability Working Group to oversee activities related to the first and second recommendations.