MOBY: Modeling Ocean Variability and Biogeochemical Cycles

Intellectual Merit: This project (MOBY) focuses on decadal predictability of the ocean component of the climate system, both in its physical and biogeochemical aspects. It will advance understanding of the coupled physical, chemical and biological processes in the ocean that respond to, and feedback on, the global climate. Physical and biogeochemical activity on the mesoscale, the scale at which most of the kinetic energy in the ocean resides, is thought to play a major role in controlling the ability of the ocean to sequester heat and carbon in to its interior on interannual to decadal timescales. The mesoscale and its interaction with biogeochemical cycles must therefore be either resolved, or understood and parameterized, before we can have confidence in decadal climate predictions. The current generation of ocean climate models, however, do not resolve the mesoscale, and, if they represent biogeochemistry at all, only a few 'compartments' are included.

To address this challenge, scientists at the Massachusetts Institute of Technology, Woods Hole Oceanographic Institution, and the National Center for Atmospheric Research, propose a multi-scale modeling approach in which regional, high-resolution models are embedded in global, coarser-scale ocean models. The resulting numerical 'zoom lenses' will be deployed in key regions of climate variability in an attempt to resolve the mesoscale and submesoscale environment experienced by ocean ecosystems, but embedded in a global model. Then, models of biogeochemical cycles will be overlain to study the interaction of ecosystems with fully-resolved mesoscale turbulence. 'Self-assembling' ecosystem models will be employed that have the capacity to represent the response of the ecosystem to the changing environment and modes of variability. Finally, the integrated effects on heat/carbon uptake, and ecosystem community structure will be studied. The global context of these calculations will allow plausible inferences to be made about the rectified effects of mesoscale physical, chemical and biological interactions and inform strategies to parameterize them in the coarser-resolution coupled climate models used in projections of decadal variability and climate change.

These overlapping activities will be focused on three regions of strong natural variability where there is vigorous small-scale variability: the equatorial Pacific, the Southern Ocean and the subtropical northwest Atlantic. The associated modes of variability are ENSO, the Southern Annular Mode (SAM), and North Atlantic Oscillation (NAO), respectively.

Broader Impacts: The proposed research is key to our understanding and modeling the ocean and life within it, the evolution of life within the ocean over earth history, the global cycle of carbon and nutrients, the conservation and exploitation of the ocean's natural resources, management of fisheries, geoengineering (to inform decisions about the pros and cons of attempting to ameliorate anthropogenic impacts) and ocean acidification, among many other grand challenges. These collaborative efforts will provide training and learning opportunities to the graduate and undergraduate students participating in the research. A current Ph.D. student in the MIT/WHOI Joint Program will be supported by this project, along with two further students. The investigators will also attempt to entrain undergraduates into the project through the WHOI Summer Student Fellowship/NSF Research Experience for Undergraduates program. Finally, in addition to yearly group meetings of the project participants (students, post-docs and scientists from the three collaborating institutions), two-day 'community workshops' in years 2 and 4 of the project will be held to inform, and be informed by a wider group of scientists working on the broad science themes embraced by the MOBY project.