Sarah Lang, Melissa Omand, Luc Lenain

Submesoscale dynamics can induce significant vertical fluxes of phytoplankton, nutrients, and carbon, resulting in biological and climatological impacts such as enhanced phytoplankton production, phytoplankton community shifts, and carbon export. However, resolving these dynamics is challenging due to their rapid evolution (hours to days) and small spatial scales (1-10 km) of variability. The Modular Aerial Sensing System (MASS), an airborne instrument package measuring concurrent ocean dynamics and hyperspectral ocean color, provides a powerful tool to study the influence of submesoscale dynamics on phytoplankton and carbon. In this study, we present the first airborne observations pairing snapshots of sub-kilometer ocean velocities and their derivatives (i.e. vorticity, divergence, and strain) with concurrent ocean color and sea surface temperature. We developed airborne proxies of chlorophyll-a and particulate organic carbon, which explained about 70.7% and 65.6% of in situ variability without the need for atmospheric correction, suggesting that MASS can detect shifts in phytoplankton distributions. We also explored relationships between concurrent vorticity, divergence, strain, sea surface temperature, chlorophyll-a, and hyperspectral variables to illuminate the submesoscale processes that alter phytoplankton distributions. This study demonstrates the value of merging bio-optical and physical airborne remote sensing data to better understand the influence of submesoscale dynamics on oceanic ecosystems and organic carbon. We highlight the potential for suborbital remote sensing to quantify processes that impact phytoplankton ecosystems and carbon transport without the spatiotemporal aliasing affecting in situ sensors.