Integrated Calendar

Submesoscale processes may strongly influence the depth and stratification of the ocean surface boundary layer, yet the prevalence of these motions throughout the ocean as well as the conditions that trigger them have been difficult to ascertain. Previous observational programs have focused on regions of strong frontal currents, such as the Gulf Stream and Kuroshio, where conditions are favorable for submesoscale instabilities. Here we present results from a unique times series of hydrographic observations, obtained at submesoscale resolution, from a region with a weak mean flow. As part of the Ocean Surface Mixing, Ocean Submesoscale Interaction Study (OSMOSIS) program, glider pairs occupied a small 20 km by 20 km region over the Porcupine Abyssal Plain in the northeast Atlantic from September 2012 to September 2013. Measurements from the gliders were complemented by a suite of nine mooring arrays in the same region. We analyze the in situ evolution in the context of the background conditions from satellite data, including sea surface temperature, sea surface height and surface forcing from wind stress reanalysis. We also analyze three months of a 1/48-degree ocean model in the same region. This data set provides an opportunity to study the physical processes that contribute to upper ocean mixed-layer variability over a full seasonal cycle.