The Fram Strait is the main passage through which mass and heat exchange between the Atlantic and Arctic Ocean takes place. A tomography experiment was conducted from September 2008 to August 2009 in the eastern Fram Strait in the framework of the DAMOCLES EU/FP6 project. The experiment involved an acoustic source west of Spitzbergen and a vertical receiving array in the middle of the strait. The one-year long series of travel-time data from the vertical receiving array are analysed to recover temperature variations along the 130- km section over the duration of the experiment. The temperature distribution is parameterized in terms of empirical orthogonal functions (EOFs) based on historical data. A Markov Chain Monte Carlo (MCMC) inversion scheme is used relying on the matched-peak approach, seeking to maximize the agreement between theoretical and measured travel times.