Southern Ocean Observations and Modeling

2013-18 Faculty Research Award

There is a growing consensus in Earth System research that the Southern Ocean, a remote and inhospitable region of the world, is a critical and under-measured gateway between the deep ocean and the surface ocean and the atmosphere. In this region, nutrients stored in the deep ocean are released to the ocean’s surface, and anthropogenic carbon and excess heat enter the deep ocean.

Observational analyses and model simulations have revealed that the Southern Ocean, which is the region south of 30°S that occupies just over one-quarter of the surface ocean area, has a profound influence on the Earth’s climate and ecosystems. This region has been found to be responsible for:

  • up to half of the annual oceanic uptake of anthropogenic carbon dioxide from the atmosphere;
  • the return of the vast majority of nutrients from the deep ocean to the surface ocean, including three-quarters of the nutrients fueling biological production north of 30°S;
  • the uptake of 70% ± 30% of the excess heat that is transferred from the atmosphere into the ocean each year; and
  • the majority of the energy input driving large-scale deep overturning circulation throughout the ocean.

Model studies also project that changes in the Southern Ocean will have a profound influence on future climate trends, with corresponding alteration of the ocean carbon cycle, heat uptake, and ecosystems.

Recent initiatives to address these challenges have been spearheaded by Jorge Sarmiento, with the goal of forming a multi-university network of researchers united with the goals of revolutionizing the data collection and modeling capabilities in the Southern Ocean. This network of scientists and their proposed research efforts represent exciting opportunities for Princeton undergraduates to get involved in multi-year cutting-edge climate research endeavors related to sensor development, calibration, and deployment; data assimilation modeling and state estimation; high-resolution forward modeling of mixing in the Southern Ocean; and outreach. This project aims to:

  • improve understanding on processes responsible for carbon and heat uptake, and on carbon, nutrients and heat transport to the ocean interior and lower latitudes.
  • improve current estimates of spatial and temporal patterns of heat and carbon uptake and nutrient utilization: and
  • predict the Southern Ocean response induced by ongoing changes in air temperature, stratification and winds over the Southern Ocean.

Pursuing these research goals will provide an enhanced understanding of how the Earth’s climate behaves thus providing the context within which any solution to climate change must be evaluated.

Educational Impacts

The project team will support 6 undergraduate researchers as well as one post-doctoral researcher. The undergraduate researchers will receive training in climate science as well as grounding in the technical skills related to computer climate modeling, sensor development or deployment, or data acquisition and synthesis. In addition, Sarmiento and the post-doctoral researcher will work with the undergraduates and encourage them to collaborate with one another and to share the expertise that each of them is gaining from their involvement in this program with each other.

Other Outcomes

In addition to mentoring undergraduates, Prof. Sarmiento teaches one of the principal entry-level introductory courses for majors in Geosciences and related fields, GEO202, Ocean, Atmosphere, and Climate. Another of the goals for this Challenge Grant is to develop a series of lecture and laboratory modules based on the Southern Ocean community sensor network so that students in GEO202 can have the experience of working with near-real time observations of the Southern Ocean. Undergraduates will have the opportunity to analyze profiles of physical variables (temperature and salinity) and biogeochemical variables (nutrients and oxygen) measured by autonomous profiling floats currently deployed in the Southern Ocean, and to track elephant seals equipped with sensors measuring temperature, salinity and fluorescence along their path in the Southern Ocean. This will come with the option of subsequently spending a summer working on a long term research project as interns with one of the universities as noted above. Our goal would be to continue to build GEO202 into a larger feeder course for majors.

Participating Department

Collaborating Institutions


George J. Magee Professor of Geoscience and Geological Engineering, Professor of Geosciences. Director, Program in Atmospheric and Oceanic Sciences

Research Associates

  • Carolina Dufour
  • Gregory de Souza

Additional Researchers

Undergraduate Students: