Eddy Length Scales in the Ross Sea From Observations and a Model

The Ross Sea is a well known high nutrient, low chlorophyll region of the ocean, with iron as the limiting resource for growth; this is the focus of the Process Regulating Iron Supply at the Mesoscale in the Ross Sea (PRISM-RS) study. The existence of mesoscale oceanic eddies as a main trains. One important feature to study is the horizontal length scale of these eddies, which are expected to be small due to the small Rossby radius of deformation in this region. To examine this, a combination of temperature, salinity, and fluorescence observations from a cruise aboard the R/V Nathaniel B. Palmer in December 2011- January 2012 and sixty days of numerical model results ran for the same period of the observations were used to identify the length scale through spatially lagged correlations. Measurement came from the Moving Vessel Profiler (MVP) and Video Plankton Recorder (VPR) instruments which produced vertical profiles of the ocean. Correlations were calculated for each track of the instruments and averaged over depth ranges. The correlations showed that the eddies and their length scales were identifiable with some distinctions based on the level of the ocean, the quantity used for comparison, and whether the measurements came from in-situ or the numerical model.