Student of the Sea: Learning the Ropes Aboard NASA’s S-MODE Mission

By Igor Uchôa, Ph.D. student at the University of Maryland in the Atmospheric and Oceanic Sciences Department // Aboard the Bold Horizon //

NASA’s S-MODE mission was designed to measure and understand the complex oceanic features classified as “submesoscale,” i.e., features spanning up to 6.2 miles (10 kilometers) across. Such fine filaments and sharp density fronts in the ocean are responsible for fast and unpredictable changes in velocity, temperature, salinity, and even among small organisms called plankton in the surface layer of the ocean. A myriad of autonomous instruments, airborne sensors, and a fully equipped ship are part of the robust methods of measuring submesoscale dynamics in the California Current region.

There are currently more than 40 scientists among researchers, students, and technicians from various institutes working together either virtually all over the country (in the control center), or in the research vessel Bold Horizon (where I currently am) sampling and streaming data for the group to analyze. Within the S-MODE science party, the air-sea interaction group attempts to understand the connections between the submesoscale filaments in the ocean and the atmosphere above them. As part of this group, learning has been my daily activity on the ship.

A science team of roughly 20 people stands on the pier in front of a research vessel.
Science team on board the R/V Bold Horizon for the second deployment of the S-MODE mission (10/07/2022). Credit: Erin Czech.

One of the tasks I am responsible for here, among other science team members, is the launching of instruments called radiosondes while the ship surveys important features in the ocean. The 200 radiosondes stocked in the ship are comprised of a foam cup, a helium-filled balloon, and a sensor. The instruments, which resemble a toy, are incredibly valuable for observing the temperature, humidity, winds, and even cloud-base height of the atmosphere in its first 3.1 miles (5 kilometers) from the surface on average.  

The ocean and atmosphere at larger scales actively interact and change each other’s properties. One of the goals of the S-MODE cruise is to find out if this also occurs in submesoscale phenomena such as cold, dense filaments in warm waters as commonly seen in the California Current region.

Three images -- on top is a photo at night of scientists on the research vessel. On the bottom left, a man releases a small balloon attached to a device that collects atmospheric data. On the right, a team aboard the ship deploys autonomous floating marine robots.
My experience on the S-MODE cruise sampling: (top) casting a sensor underway for vertical sections of oceanographic properties such as temperature, salinity, chlorophyll, and dissolved oxygen, (left) launching a radiosonde in calm weather conditions, (right) Avery Snyder, Gwendal Marechal, Jessica Kozic, and I on the deployment of Lagrangian floats for tracking and measuring properties of submesoscale features. Credit: Alexis Arends, Andrey Shcherbina.

Installing those sensors is a relatively easier task than the high-tech instruments found on the research vessel, but the practical launching is sometimes a bit… daunting. Knowing how to tie a balloon suddenly becomes essential when you must launch many radiosondes in a small window of time in a rocking ship in windy weather. Also, becoming an expert observer of wind direction is a must-have skill, or else expensive sensors become tangled in the ship and lost forever. It is still a fun procedure, nonetheless, which brings very useful information to the puzzle of understanding air-sea interaction in the submesoscale.

Throughout the process of helping the team launch S-MODE and bring useful data to the group, I had to learn how to take more initiative. I gradually felt that I became part of the plan-of-action for the survey, which I believe is very important for a scientific career, especially for a Ph.D. student like me. Being part of such a high-level research mission is both an overwhelming and exciting learning experience. We still have many days to go, but I am certain that this cruise has already taught me a lot.