A Bayesian adaptive ensemble Kalman filter for sequential state and   parameter estimation
  This paper proposes new methodology for sequential state and parameter estimation within the ensemble Kalman filter. The method is fully Bayesian and propagates the joint posterior density of states and parameters over time. In order to implement the method we consider two representations of the marginal posterior distribution of the parameters: a grid-based approach and a Gaussian approximation. Contrary to existing algorithms, the new method explicitly accounts for parameter uncertainty and provides a formal way to combine information about the parameters from data at different time periods. The method is illustrated and compared to existing approaches using simulated and real data. 
Jonathan R. Stroud, Matthias Katzfuss, and Christopher K. Wikle
stat.ME stat.CO