Master thesis defense by Steffen Ole Randrup Kristensen

Title: Extending the Veros climate simulator with biochemistry

Abstract: Marine biogeochemistry poses a set of nonlinear coupled problems. Biogeochemistry covers a large variety of components, each with varying importance in different regions. This raises an issue for models of providing functionality for many possible combinations of actively tracked components and the dynamical systems between them with as little overhead as possible. When models provide multiple configuration options, they must maintain each combination of possible options, which in many models has lead to complex, difficult to maintain code structures. This limits the availability of the model for new users and may require significant introduction times. I propose a different model design, which is able to accommodate configuration options without the combinatorial problems of other designs, and allows for easy addition of new features without the risk of breaking existing functionality. The design is implemented as a module to the "Versatile Ocean Simulation in Pure Python", Veros. I discuss the design choices and requirements for a modern, approachable biogeochemistry simulation model, and present results produced by the implemented design. Finally I simulate a weakening of the Atlantic meridional overturning circulation and analyze the results on global biogeochemistry.