A 1-day workshop will be held in Woods Hole on Sunday, June 23 just before the OCB workshop for those interested in using an ocean circulation inverse model (OCIM) in their research. The OCIM is a data-constrained, lightweight, MATLAB-based ocean circulation model for global modeling of biogeochemical tracers. It has been used to model nutrients, carbon, oxygen, trace metals, and marine food webs, among others. Workshop participants will be provided with model code and instructions, and will engage in tutorial sessions designed to promote familiarity with the model and ability to design and run biogeochemical simulations. Examples of topics that might be covered include: age and water-mass tracers, preformed tracers, diagnostic calculations, transient tracers, air-sea gas exchange, organic matter production and remineralization, isotopes, non-linear models and Newton’s method, iterative solvers, and optimization. Workshop is limited to 20 participants. Requirements: a laptop computer with MATLAB installed and at least 8 GB RAM. Recommended: Working knowledge of MATLAB. Please direct questions to Tim DeVries at email@example.com.